THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

RIVERSIDE 


DRAGONS   OF   THE   AIR 


DRAGONS  OF  THE  AIR 

AN   ACCOUNT  OF 
EXTINCT  FLYING  REPTILES 


H.  G.  SEELEY,  F.R.S. 

PROFESSOR   OF   GEOLOGY  IN    KING'S  COLLEGE,    LONDON  J    LECTURER  ON    GEOLOGY 
AND   MINERALOGY   IN   THE   ROYAL   INDIAN    ENGINEERING   COLLEGE 


WITH   EIGHTY   ILLUSTRATIONS 


Job  xxx.  29 


NEW  YORK:   D.  APPLETON  &  CO. 

LONDON:    METHUEN  &  CO. 

1901 


PREFACE 


T  WAS  a  student  of  law  at  a  time  when  Sir 
-*-  Richard  Owen  was  lecturing  on  Extinct  Fossil 
Reptiles.  The  skill  of  the  great  master,  who  built 
bones  together  as  a  child  builds  with  a  box  of 
bricks,  taught  me  that  the  laws  which  determine  the 
forms  of  animals  were  less  understood  at  that  time 
than  the  laws  which  govern  the  relations  of  men  in 
their  country.  The  laws  of  Nature  promised  a  better 
return  of  new  knowledge  for  reasonable  study.  A 
lecture  on  Flying  Reptiles  determined  me  to  attempt 
to  fathom  the  mysteries  which  gave  new  types  of  life 
to  the  Earth  and  afterwards  took  them  away. 

Thus  I  became  the  very  humble  servant  of  the 
Dragons  of  the  Air.  Knowing  but  little  about  them 
I  went  to  Cambridge,  and  for  ten  years  worked  with 
the  Professor  of  Geology,  the  late  Rev.  Adam  Sedg- 
wick,  LL.D.,  F.R.S.,  in  gathering  their  bones  from  the 
so-called  Cambridge  Coprolite  bed,  the  Cambridge 
Greensand.  The  bones  came  in  thousands,  battered 
and  broken,  but  instructive  as  better  materials  might 


vi  PREFACE 

not  have  been.  My  rooms  became  filled  with  remains 
of  existing  birds,  lizards,  and  mammals,  which  threw 
light  on  the  astonishing  collection  of  old  bones  which 
I  assisted  in  bringing  together  for  the  University. 

In  time  I  had  something  to  say  about  Flying 
Animals  which  was  new.  The  story  was  told  in 
the  theatre  of  the  Royal  Institution,  in  a  series 
of  lectures.  Some  of  them  were  repeated  in  several 
English  towns.  There  was  still  much  to  learn  of 
foreign  forms  of  flying  animals  ;  but  at  last,  with 
the  aid  of  the  Government  grant  administered  by  the 
Royal  Society,  and  the  chiefs  of  the  great  Continental 
museums,  I  saw  all  the  specimens  in  Europe. 

So  I  have  again  written  out  my  lectures,  with  the 
aid  of  the  latest  discoveries,  and  the  story  of  animal 
structure  has  lost  nothing  in  interest  as  a  twice-told 
tale.  It  still  presents  in  epitome  the  story  of  life  on 
the  Earth.  He  who  understands  whence  the  Flying 
Reptiles  came,  how  they  endured,  and  disappeared 
from  the  Earth,  has  solved  some  of  the  greatest 
mysteries  of  life.  I  have  only  contributed  something 
towards  solving  the  problems. 

In  telling  my  story,  chiefly  of  facts  in  Nature,  an 
attempt  is  made  to  show  how  a  naturalist  does  his 
work,  in  the  hope  that  perhaps  a  few  readers  will  find 
happiness  in  following  the  workings  of  the  laws  of 
life.  Such  an  illumination  has  proved  to  many 
worth  seeking,  a  solid  return  for  labour,  which  is 


PREFACE  ,        vii 

not  to  be  marketed  on  the  Exchange,  but  may  be 
taken  freely  without  exhausting  the  treasury  of 
Nature's  truths.  Such  outlines  of  knowledge  as 
here  are  offered  to  a  larger  public,  may  also,  I 
believe,  be  acceptable  to  students  of  science  and 
scientific  men. 

The  drawings  given  in  illustration  of  the  text  have 
been  made  for  me  by  Miss  E.  B.  Seeley. 

H.  G.  S. 

KENSINGTON,  May,  1901 


CONTENTS 


CHAPTER   I. 

PACK 

FLYING  REPTILES  .  I 

CHAPTER    II. 
HOW  A  REPTILE  IS  KNOWN  .  ...          4 

CHAPTER   III. 
A   REPTILE  IS   KNOWN   BY  ITS   BONES  .  II 

CHAPTER   IV. 
ANIMALS  WHICH   FLY         .  .  .  .          .         15 

CHAPTER   V. 
DISCOVERY  OF  THE  PTERODACTYLS  . "  .          .        27 

CHAPTER   VI. 
HOW  ANIMALS  ARE  INTERPRETED   BY  THEIR  BONES       .        37 

CHAPTER    VII. 

INTERPRETATION  OF  PTERODACTYLES  BY  THEIR  SOFT 

PARTS     .        .        .        ...   45 

CHAPTER   VIII. 
THE  PLAN   OF  THE  SKELETON         ..  .  58 

CHAPTER   IX. 
THE   BACKBONE,   OR  VERTEBRAL  COLUMN    .  78 


x  CONTENTS 

CHAPTER   X. 

PAGE 

THE  HIP-GIRDLE  AND  HIND  LIMB  .  93 

CHAPTER   XI. 
SHOULDER-GIRDLE  AND   FORE  LIMB  .  .      107 

CHAPTER   XII. 
EVIDENCES  OF  THE  ANIMAL'S  HABITS  FROM  ITS  REMAINS      134 

CHAPTER  XIII. 
ANCIENT  ORNITHOSAURS   FROM  THE   LIAS    .  .  .143 

CHAPTER  XIV. 
ORNITHOSAURS   FROM  THE   MIDDLE   SECONDARY  ROCKS      153 

CHAPTER   XV. 
ORNITHOSAURS  FROM   THE  UPPER  SECONDARY   ROCKS.      172 

CHAPTER   XVI. 
CLASSIFICATION  OF  THE  ORNITHOSAURIA   .  .          .187 

CHAPTER   XVII. 

FAMILY    RELATIONS    OF    PTERODACTYLES    TO    ANIMALS 

WHICH  LIVED  WITH  THEM       .  .  .      196 

CHAPTER   XVIII. 
HOW  PTERODACTYLES  MAY   HAVE  ORIGINATED         .  .213 

APPENDIX  .  .  .  .  .  .      231 

INDEX  .  .  .  ...      233 


LIST  OF  ILLUSTRATIONS 


FIG.  PAGE 

47.  Wings  of  Rhamphorhynchus  .  .  Frontispiece 

1.  Lung  of  the  lung-fish  Ceratodus       .  ...  5 

2.  Attachment   of   the   lower  jaw   in   a    Mammal  and  in  a 

Pterodactyle               .                 .  .             »         .  12 

3.  Chaldrean  Dragon              .                 .  .  15 

4.  Winged  human  figure  from  the  Temple  of  Ephesus     .         .  16 

5.  Flying  fish  Exoccetus        .                .  .            .         .  18 

6.  Flying  Frog       .                .                .  .            .         .  19 

7.  Flying  Lizard  (Draco)       .                 .  ...  20 

8.  Birds  in  flight    .                 .                 .  ...  22 

9.  Flying  Squirrel  (Pteromys)                .  .  24 

10.  Bats,  flying  and  walking  .                .  ...  25 

11.  Skeleton  of  Pterodactyhis  longirostris  .  28 

12.  The  skeleton  restored       .                .  ...  29 

13.  The  animal  form  restored                  .  .  30 

14.  Fore  limbs  in  four  types  of  mammals  .  38 

15.  Pneumatic  foramen  in  Pterodactyle  bone  .  .         ,46 

1 6.  Lungs  of  the  bird  Apteryx                 .  .             .         .  48 

17.  Air  cells  in  the  body  of  an  Ostrich  .  .  49 

1 8.  Lung  of  a  Chameleon       .                .  .  51 

19.  Brain  in  Pterodactyle,  Mammal,  Bird,  and  Reptiles    .         .  53 

20.  Skull  of  Kingfisher  and  Rhamphorhynchus  .  63 

21.  Skull  of  Heron  and  Rhamphorhynchus  .  65 

22.  Palate  of  Macrocercus  and  ?  Campylognathus               .         .  71 

23.  Lower  jaw  of  Echidna  and  Ornithostoma  .  .         .76 

24.  First  two  neck  vertebrae  of  Ornithocheirus  .  .         .81 


LIST   OF   ILLUSTRATIONS 


PAGF 


25.  Middle  neck  vertebrae  of  Ornithocheirus          .  83 

26.  Back  vertebra  of  Ornithocheirus  and  Crocodile  .         .       86 

27.  Sacrum,  with  hip  bones,  of  Rhamphorhynchus  .         .       88 

28.  Extremity  of  tail  of  Rhamphorhynchus  phyllurus        .         .       91 

29.  Hip-girdle  bones  in  Apteryx  and  Rhamphorhynchus    .         .       95 

30.  Pelvis  with  prepubic  bone  in  Pterodactylus      .  96 

31.  Pelvis  with  prepubic  bones  in  Rhamphorhynchus        .         .       97 

32.  Pelvis  of  an  Alligator  seen  from  below  .  .         .       98 

33.  Femora :  Echidna,  Ornithocheirus,  Ursus        .  .         .     100 

34.  Tibia  and  fibula  :  Dimorphodon  and  Vulture  .  .         .102 

35.  Metatarsus  and  digits  in  three  Pterodactyles    .  .         .     104 

36.  Sternum  in  Cormorant  and  Rhamphorhynchus  .         .108 

37.  Sternum  in  Ornithocheirus  .  .  .     109 

38.  Shoulder-girdle  bones  in  a  bird  and  three  Pterodactyles       .     113 

39.  The  Notarium  from  the  back  of  Ornithocheirus  .         -US 

40.  The  shoulder-girdle  of  Ornithocheirus  .  .         -US 

41.  Humerus  of  Pigeon  and  Ornithocheirus  .  .         .119 

42.  Fore-arm  of  Golden  Eagle  and  Dimorphodon  .         .120 

43.  Wrist  bones  of  Ornithocheirus          .  .  .         .     124 

44.  Clawed  digits  of  the  hand  in  two  Pterodactyles  .         .125 

45.  Claw  from  the  hand  of  Ornithocheirus  .  .         .129 

46.  The  hand  in  Archteopteryx  and  the  Ostrich     .  .         .130 

48.  Slab  of  Lias  with  bones  of  Dimorphodon         .      To  face  page  143 

49.  Dimorphodon  (restored  form)  at  rest  .  .         .     144 

50.  Dimorphodon  (restored  form  of  the  animal)     .      To  face  page  145 

51.  Dimorphodon  skeleton,  walking  as  a  quadruped        „        „      146 

52.  Dimorphodon  skeleton  as  a  biped    .  „        „      147 

53.  Lower  jaw  of  Dorygnathus  .  ...     149 

54.  Dimorphodon  (wing  membranes  spread  for  flight)  To  face  page  150 

55.  Pelvis  of  Dimorphodon     .  .  .  .         .     151 

56.  Rhamphorhynchus  skeleton  (restored)  .  .         .     161 

57.  Scaphognathus  (restoration  of  1875)  .  .         .     163 

58.  Six  restorations  of  Ornithosaurs       .  .  .     164 

59.  Ptenodracon  skeleton  (restored)        .  .  .     167 

60.  Cycnorhamphus  suevtcus  slab  with  bones         .      To  face  page  168 

61.  Cycnorhamphus  suevtcus  (form  of  the  animal)      To  face  page  169 

62.  Cycnorhamphus  suevicus  skeleton  (restored)    .  .         .170 


LIST    OF    ILLUSTRATIONS  xiii 

PAGE 

63.  Cycnorhamphus   Fraasi   (restored    skeleton    form    of    the 

animal)  ;.  .  .      To  face  page  170 

64.  Cycnorhamphus   Fraasi   (restoration   of   the   form   of    the 

body)                     .                 .                 .     To  face  page  1 7 1 

65.  Neck  vertebra  of  Doratorhynchus  from  the  Purbeck    .  .173 

66.  Neck  bone  of  Ornithodesmus  from  the  Wealden          .  .     173 

67.  Sternum  of  Ornithodesmus,  seen  from  the  front           .  .     175 

68.  Sternum  of  Ornithodesmus,  side  view,  showing  the  keel  .     175 

69.  Diagram  of  known  parts  of  skull  of  Ornithocheirus    .  .     177 

70.  Neck  bone  of  Ornithocheirus           .                .             .  .     179 

71.  Jaws  of  Ornithocheirus  from  the  Chalk            .            .  .180 

72.  Palate  of  the  English  Toothless  Pterodactyle  .            .  .     181 

73.  Two  views  of  the  skull  of  Ornithostoma  (Pteranodon)  .     182 

74.  Skeleton  of  Ornithostoma                 .                .             .  .     183 

75.  Comparison  of  six  skulls  of  Ornithosaurs        .             .  .     192 

76.  Pelvis  of  Ornithostoma     .                 .                 .  .     195 

77.  Skull  of  Anchisaurus  and  Dimorphodon           .             .  .     199 

78.  Skull  of  Ornithosuchus  and  Dimorphodon       .             .  .     201 

79.  The  pelvis  in  Ornithosaur  and  Dinosaur           .             .  .     204 

80.  The  prepubic  bones  in  Dimorphodon  and  Iguanodon  .  .     206 

These  figures  are  greatly  reduced  in  size,  and  when  two  or  more  bones  are  shown 
in  the  same  figure  all  are  brought  to  the  same  size  to  facilitate  the  comparison. 


DRAGONS  OF  THE  AIR 

CHAPTER    I 
FLYING    REPTILES 

THE  history  of  life  on  the  earth  during  the 
epochs  of  geological  time  unfolds  no  more 
wonderful  discovery  among  types  of  animals  which 
have  become  extinct  than  the  family  of  fossils  known 
as  flying  reptiles.  Its  coming  into  existence,  its 
structure,  and  passing  away  from  the  living  world 
are  among  the  great  mysteries  of  Nature. 

The  animals  are  astonishing  in  their  plan  of  con- 
struction. In  aspect  they  are  unlike  birds  and  beasts 
which,  in  this  age,  hover  over  land  and  sea.  They 
gather  into  themselves  in  the  body  of  a  single  indi- 
vidual, structures  which,  at  the  present  day,  are 
among  the  most  distinctive  characters  of  certain 
mammals,  birds,  and  reptiles. 

The  name  "  flying  reptile  "  expresses  this  anomaly. 
Its  invention  is  due  to  the  genius  of  the  great  French 
naturalist  Cuvier,  who  was  the  first  to  realise  that  this 
extinct  animal,  entombed  in  slabs  of  stone,  is  one  of 
the  wonders  of  the  world. 

The  word  "  reptile  "  has  impressed  the  imagination 
with  unpleasant  sound,  even  when  the  habits  of  the 


2  DRAGONS   OF   THE   AIR 

animals  it  indicates  are  unknown.  It  is  familiarly 
associated  with  life  which  is  reputed  venomous,  and 
is  creeping  and  cold.  Its  common  type,  the  serpent, 
in  many  parts  of  the  world  takes  a  yearly  toll  of 
victims  from  man  and  beast,  and  has  become  the 
representative  of  silent,  active  strength,  dreaded  craft, 
and  danger. 

Science  uses  the  word  "reptile"  in  a  more  exact 
way,  to  define  the  assemblage  of  cold-blooded  animals 
which  in  familiar  description  are  separately  named 
serpents,  lizards,  turtles,  hatteria,  and  crocodiles. 

Turtles  and  the  rest  of  them  survive  from  great 
geological  antiquity.  They  present  from  age  to  age 
diversity  of  aspect  and  habit,  and  in  unexpected 
differences  of  outward  proportion  of  the  body  show 
how  the  laws  of  life  have  preserved  each  animal  type. 
For  the  vital  organs  which  constitute  each  animal 
a  reptile,  and  the  distinctive  bony  structures  with 
which  they  are  associated,  remain  unaffected,  or  but 
little  modified,  by  the  animal's  external  change  in 
appearance. 

The  creeping  reptile  is  commonly  imagined  as  the 
antithesis  of  the  bird.  For  the  bird  overcomes  the 
forces  that  hold  even  man  to  the  earth,  and  enjoys 
exalted  aerial  conditions  of  life.  Therefore  the  marvel 
is  shared  equally  by  learned  and  unlearned,  that  the 
power  of  flight  should  have  been  an  endowment  of 
animals  sprung  from  the  breed  of  serpents,  or  croco- 
diles, enabling  them  to  move  through  the  air  as 
though  they  too  were  of  a  heaven-born  race.  The 
wonder  would  not  be  lessened  if  the  animal  were 
a  degraded  representative  of  a  nobler  type,  or  if 
it  should  be  demonstrated  that  even  beasts  have 
advanced  in  the  battle  of  life.  The  winged  reptile, 


FLYING   REPTILES  3 

when  compared  with  a  bird,  is  not  less  astounding 
than  the  poetic  conceptions  in  Milton's  Paradise 
Lost  of  degradation  which  overtakes  life  that  once 
was  amongst  the  highest.  And  on  the  other  hand, 
from  the  point  of  view  of  the  teaching  of  Darwin 
in  the  theories  of  modern  science,  we  are  led  to  ask 
whether  a  flying  reptile  may  not  be  evidence  of  the 
physical  exaltation  which  raises  animals  in  the  scale 
of  organisation.  The  dominance  upon  the  earth  of 
flying  reptiles  during  the  great  middle  period  of 
geological  history  will  long  engage  the  interest 
of  those  who  can  realise  the  complexity  of  its 
structure,  or  care  to  unravel  the  meaning  of  the 
procession  of  animal  forms  in  successive  geological 
ages  which  preceded  the  coming  of  man. 

The  outer  vesture  of  an  animal  counts  for  little  in 
estimating  the  value  of  ties  which  bind  orders  of 
animals  together,  which  are  included  in  the  larger 
classes  of  life.  The  kindred  relationship  which  makes 
the  snake  of  the  same  class  as  the  tortoise  is  deter- 
mined by  the  soft  vital  organs — brain,  heart,  lungs — 
which  are  the  essentials  of  an  animal's  existence  and 
control  its  way  of  life.  The  wonder  which  science 
weaves  into  the  meaning  of  the  word  "  reptile,"  "  bird," 
or  "  mammal,"  is  partly  in  exhibiting  minor  changes 
of  character  in  those  organs  and  other  soft  parts,  but 
far  more  in  showing  that  while  they  endure  un- 
changed, the  hard  parts  of  the  skeleton  are  modified 
in  many  ways.  For  the  bones  of  the  reptile  orders 
stretch  their  affinities  in  one  direction  towards  the 
skeletons  of  salamanders  and  fishes ;  and  extend 
them  also  at  the  same  time  in  other  directions, 
towards  birds  and  mammals.  This  mystery  we  may 
hope  to  partly  unravel. 


CHAPTER   II 
HOW   A    REPTILE    IS    KNOWN 

DEFINITION   OF   REPTILES   BY   THEIR 
VITAL  ORGANS 

THE  relations  of  reptiles  to  other  animals  may  be 
stated  so  as  to  make  evident  the  characters  and 
affinities  which  bind  them  together.  Early  in  the 
nineteenth  century  naturalists  included  with  the  Rep- 
tilia  the  tribe  of  salamanders  and  frogs  which  are 
named  Amphibia.  The  two  groups  have  been  sepa- 
rated from  each  other  because  the  young  of  Amphibia 
pass  through  a  tadpole  stage  of  development.  They 
then  breathe  by  gills,  like  fishes,  taking  oxygen  from 
the  air  which  is  suspended  in  water,  before  lungs  are 
acquired  which  afterwards  enable  the  animals  to  take 
oxygen  directly  from  the  air.  The  amphibian  some- 
times sheds  the  gills,  and  leaves  the  water  to  live  on 
land.  Sometimes  gills  and  lungs  are  retained  through 
life  in  the  same  individual.  This  amphibian  con- 
dition of  lung  and  gill  being  present  at  the  same 
time  is  paralleled  by  a  few  fishes  which  still  exist, 
like  the  Australian  Ceratodus,  the  lung-fish,  an  ancient 
type  of  fish  which  belongs  to  early  days  in  geological 
time. 

This  metamorphosis  has  been  held  to  separate  the 

4 


HOW   A   REPTILE   IS   KNOWN 


5 


amphibian  type  from  the  reptile  because  no  existing 
reptile  develops  gills  or  undergoes  a  metamorphosis. 
Yet  the  character  may  not  be  more  im- 
portant as  a  ground  for  classification 
than  the  community  of  gills  and  lungs 
in  the  fish  and  amphibian  is  ground  for 
putting  them  together  in  one  natural 
group.  For  although  no  gills  are  found 
in  reptiles,  birds,  or  mammals,  the 
embryo  of  each  in  an  early  stage  of 
development  appears  to  possess  gill- 
arches,  and  gill -clefts  between  them, 
through  which  gills  might  have  been 
developed,  even  in  the  higher  verte- 
brates, if  the  conditions  of  life  had 
been  favourable  to  such  modification 
of  structure.  In  their  bones  Reptiles 
and  Amphibia  have  much  in  common. 
Nearly  all  true  reptiles  lay  eggs,  which 
are  defined  like  those  of  birds  by  com- 
paratively large  size,  and  are  contained 
in  shells.  This  condition  is  not  usual 
in  amphibians  or  fishes.  When  hatched 
the  young  reptile  is  completely  formed, 
the  image  of  its  parent,  and  has  no  need  FIG-  l 

.  .  .   .       ...  LUNG  OF  THE  FISH 

to  grow  a  covering  to  its  skin  like  some       CERATODUS 
birds,  or  shed  its  tail  like  some  tadpoles.  Partly  laid  open  to  show 

r  its  chambered  structure 

The  reptile  is  like  the  bird  in  freedom  (After  camber) 
from  important  changes  of  form  after  the  egg  is 
hatched  ;  and  the  only  structure  shed  by  both  is  the 
little  horn  upon  the  nose,  with  which  the  embryo 
breaks  the  shell  and  emerges  a  reptile  or  a  bird, 
growing  to  maturity  with  small  subsequent  variations 
in  the  proportions  of  the  body. 


6  DRAGONS   OF  THE   AIR 

THE   REPTILE   SKIN 

Between  one  class  of  animals  and  another  the 
differences  in  the  condition  of  the  skin  are  more 
or  less  distinctive.  In  a  few  amphibians  there  are 
some  bones  in  the  skin  on  the  under  side  of  the 
body,  though  the  skin  is  usually  naked,  and  in  frogs 
is  said  to  transmit  air  to  the  blood,  so  as  to  exercise 
a  respiratory  function  of  a  minor  kind.  This  naked 
condition,  so  unlike  the  armoured  skin  of  the  true 
Reptilia,  appears  to  have  been  paralleled  by  a  number 
of  extinct  groups  of  fossils  of  the  Secondary  rocks, 
such  as  Ichthyosaurs  and  Plesiosaurs,  which  were 
aquatic,  and  probably  also  by  some  Dinosauria,  which 
were  terrestrial. 

Living  reptiles  are  usually  defended  with  some 
kind  of  protection  to  the  skin.  Among  snakes  and 
lizards  the  skin  has  commonly  a  covering  of  over- 
lapping scales,  usually  of  horny  or  bony  texture. 
The  tortoise  and  turtle  tribe  shut  up  the  animal  in  a 
true  box  of  bone,  which  is  cased  with  an  armour  of 
horny  plates.  Crocodiles  have  a  thick  skin  em- 
bedding a  less  continuous  coat  of  mail.  Thus  the 
skin  of  a  reptile  does  not  at  first  suggest  anything 
which  might  become  an  organ  of  flight ;  and  its 
dermal  appendages,  or  scales,  may  seem  further  re- 
moved from  the  feathers  which  ensure  flying  powers 
to  the  bird  than  from  the  naked  skin  of  a  frog. 

THE    REPTILE    BRAIN 

Although  the  mode  of  development  of  the  young 
and  the  covering  of  the  skin  are  conspicuous  among 
important  characters  by  which  animals  are  classified, 
the  brain  is  an  organ  of  some  importance,  although 


HOW   A   REPTILE    IS   KNOWN  7 

of  greater  weight  in  the  higher  Vertebrata  than  in  its 
lower  groups.  Reptiles  have  links  in  the  mode  of 
arrangement  of  the  parts  of  their  brains  with  fishes 
and  amphibians.  The  regions  of  that  organ  are  com- 
monly arranged  in  pairs  of  nervous  masses,  known 
as  (i)  the  olfactory  lobes,  (2)  the  cerebrum,  behind 
which  is  the  minute  pineal  body,  followed  by  (3)  the 
pair  of  optic  lobes,  and  hindermost  of  all  (4)  the 
single  mass  termed  the  cerebellum.  These  parts  of 
the  brain  are  extended  in  longitudinal  order,  one 
behind  the  other  in  all  three  groups.  The  olfactory 
lobes  of  the  brain  in  Fishes  may  be  as  large  as 
the  cerebrum  ;  but  among  Reptiles  and  Amphibians 
they  are  relatively  smaller,  and  they  assume  more  of 
the  condition  found  in  mammals  like  the  Hare  or 
Mole,  being  altogether  subordinate  in  size.  And  the 
cerebral  masses  begin  to  be  wider  and  higher  than 
the  other  parts  of  the  brain,  though  they  do  not  extend 
forward  above  the  olfactory  lobes,  as  is  often  seen  in 
Mammals.  In  Crocodiles  the  cerebral  hemispheres 
have  a  tendency  to  a  broad  circular  form.  Among 
Chelonian  reptiles  that  region  of  the  brain  is  more 
remarkable  for  height.  Lizards  and  Ophidians  both 
have  this  part  of  the  brain  somewhat  pear-shaped, 
pointed  in  front,  and  elongated.  The  amphibian 
brain  only  differs  from  the  lizard  type  in  degree ;  and 
differences  between  lizards'  and  amphibian  brains  are 
less  noticeable  than  between  the  other  orders  of 
reptiles.  The  reptilian  brain  is  easily  distinguished 
from  that  of  all  other  animals  by  the  position  and 
proportions  of  its  regions  (see  Fig.  19,  p.  53). 

Birds  have  the  parts  of  the  brain  formed  and 
arranged  in  a  way  that  is  equally  distinctive.  The 
cerebral  lobes  are  relatively  large  and  convex,  and 


8  DRAGONS    OF   THE   AIR 

deserve  the  descriptive  name  "hemispheres."  They 
are  always  smooth,  as  among  the  lower  Mammals, 
and  extend  backward  so  as  to  abut  against  the  hind 
brain,  termed  the  cerebellum.  This  junction  is 
brought  about  in  a  peculiar  way.  The  cerebral 
hemispheres  in  a  bird  do  not  extend  backward  to 
override  the  optic  lobes,  and  hide  them,  as  occurs 
among  adult  mammals,  but  they  extend  back  be- 
tween the  optic  lobes,  so  as  to  force  them  apart  and 
push  them  aside,  downward  and  backward,  till  they 
extend  laterally  beyond  the  junction  of  the  cerebrum 
with  the  cerebellum.  The  brain  of  a  Bird  is  never 
reptilian  ;  but  in  the  young  Mammal  the  brain  has 
a  very  reptilian  aspect,  because  both  have  their  parts 
primarily  arranged  in  a  line.  Therefore  the  brain 
appears  to  determine  the  boundary  between  bird 
and  reptile  exactly 


REPTILIAN   BREATHING   ORGANS 

The  breathing  organs  of  Birds  and  Reptiles  which 
are  associated  with  these  different  types  of  brain  are 
not  quite  the  same.  The  Frog  has  a  cellular  lung 
which,  in  the  details  of  the  minute  sacs  which  branch 
and  cluster  at  the  terminations  of  the  tubes,  is  not 
unlike  the  condition  in  a  Mammal.  In  a  mammal 
respiration  is  aided  by  the  bellows-like  action  of  the 
muscles  connected  with  the  ribs,  which  encase  the 
cavity  where  the  lungs  are  placed,  and  this  structure 
is  absent  in  the  Frog  and  its  allies.  The  Frog,  on  the 
other  hand,  has  to  swallow  air  in  much  the  same  way 
as  man  swallows  water.  The  air  is  similarly  grasped 
by  the  muscles,  and  conveyed  by  them  downward  to 
the  lungs.  Therefore  a  Frog  keeps  its  mouth  shut, 


HOW   A   REPTILE   IS   KNOWN  9 

and  the  animal  dies  from  want  of  air  if  its  mouth  is 
open  for  a  few  minutes. 

Crocodiles  commonly  lie  in  the  sun  with  their 
mouths  widely  open.  The  lungs  in  both  Crocodiles 
and  Turtles  are  moderately  dense,  traversed  by  great 
bronchial  tubes,  but  do  not  differ  essentially  in  plan 
from  those  of  a  Frog,  though  the  great  branches  of 
the  bronchial  tubes  are  stronger,  and  the  air  chambers 
into  which  the  lung  is  divided  are  somewhat  smaller. 
The  New  Zealand  Hatteria  has  the  lungs  of  this 
cellular  type,  though  rather  resembling  the  amphibian 
than  the  Crocodile.  The  lungs  during  life  in  all 
these  animals  attain  considerable  size,  the  maximum 
dimensions  being  found  in  the  terrestrial  tortoises, 
which  owe  much  of  their  elevated  bulk  to  the  dimen- 
sions of  the  air  cells  which  form  the  lungs. 

The  lungs  of  Serpents  and  Lizards  are  formed  on 
a  different  plan.  In  both  those  groups  of  reptiles 
the  dense  cellular  tissue  is  limited  to  the  part  of  the 
lung  which  is  nearest  to  the  throat.  This  network 
of  blood  vessels  and  air  cells  extends  about  the 
principal  bronchial  tube  much  as  in  other  animals, 
but  as  it  extends  backward  the  blood  vessels  become 
few  until  the  tubular  lung  appears  in  its  hinder  part, 
as  it  extends  down  the  body,  almost  as  simple  in 
structure  as  the  air  bladder  of  a  fish.  Among  Ser- 
pents only  one  of  these  tubular  lungs  is  commonly 
present,  and  the  structure  has  a  less  efficient  appear- 
ance as  a  breathing  organ  than  the  single  lung  of  the 
fish  Ceratodus  (Fig.  i ).  The  Chameleons  are  a  group  of 
lizards  which  differ  in  many  ways  from  most  of  their 
nearest  kindred,  and  the  lungs,  while  conforming  in 
general  plan  to  the  lizard  type  in  being  dense  at  the 
throat,  and  a  tubular  bladder  in  the  body,  give  off 


io  DRAGONS   OF  THE   AIR 

on  both  sides  a  number  of  short  lateral  branches 
like  the  fingers  of  a  glove  (Fig.  18,  p.  51). 

Thus  the  breathing  organs  of  reptiles  present  two 
or  three  distinct  types  which  have  caused  Serpents 
and  Lizards  to  be  associated  in  one  group  by  most 
naturalists  who  have  studied  their  anatomy ;  while 
Crocodiles  and  Chelonians  represent  a  type  of  lung 
which  is  quite  different,  and  in  those  groups  has 
much  in  common.  These  characters  of  the  breath- 
ing organs  contribute  to  separate  the  cold-blooded 
armoured  reptiles  from  the  warm-blooded  birds 
clothed  with  feathers,  as  well  as  from  the  warm- 
blooded mammals  which  suckle  their  young ;  for  both 
these  higher  groups  have  denser  and  more  elastic 
spongy  lung  tissue. 

It  will  be  seen  hereafter  that  many  birds  in  the 
most  active  development  of  their  breathing  organs 
substantially  revert  to  the  condition  of  the  Serpent 
or  Chameleon  in  a  somewhat  modified  way.  Because, 
instead  of  having  one  great  bronchial  tube  expanded 
to  form  a  vast  reservoir  of  air  which  can  be  dis- 
charged from  the  lung  in  which  the  reptile  has 
accumulated  it,  the  bird  has  the  lateral  branches 
of  the  bronchial  tubes  prolonged  so  as  to  pierce  the 
walls  of  the  lung,  when  its  covering  membrane  ex- 
pands to  form  many  air  cells,  which  fill  much  of  the 
cavity  of  the  bird's  body  (see  Fig.  16).  Thus  the  bird 
appears  to  combine  the  characters  of  such  a  lung  as 
that  of  a  Crocodile,  with  a  condition  which  has  some 
analogy  with  the  lung  of  a  Chameleon.  It  is  this  link 
of  structure  of  the  breathing  organs  between  reptiles 
and  birds  that  constitutes  one  of  the  chief  interests 
of  flying  reptiles,  for  they  prove  to  have  possessed 
air  cells  prolonged  from  the  lungs,  which  extended 
into  the  bones. 


CHAPTER   III 

A    REPTILE    IS    KNOWN    BY    ITS 
BONES 

SUCH  are  a  few  illustrations  of  ways  in  which 
reptiles  resemble  other  animals,  and  differ  from 
them,  in  the  organs  by  means  of  which  the  classifi- 
cation of  animals  is  made.  But  such  an  idea  is 
incomplete  without  noticing  that  the  bony  framework 
of  the  body  associated  with  such  vital  organs  also 
shows  in  its  chief  parts  that  reptiles  are  easily  recog- 
nised by  their  bones.  I  will  therefore  briefly  state 
how  reptiles  are  defined  in  some  regions  of  the 
skeleton,  for  in  tracing  the  history  of  reptile  life 
the  bones  are  the  principal  remains  of  animals 
preserved  in  the  rocks  ;  and  the  soft  organs  which 
have  perished  can  only  be  inferred  to  have  been 
present  from  the  persistence  of  durable  characteristic 
parts  of  the  skeleton,  which  are  associated  with  those 
soft  organs  in  animals  which  exist  at  the  present  day, 
and  are  unknown  in  other  animals  in  which  the 
skeleton  is  different. 

THE    HANG   OF  THE   LOWER  JAW 
The  manner  in  which  the  lower  jaw  is  connected 
with  the  skull  yields  one  of  the  most  easily  recog- 


12  DRAGONS   OF   THE   AIR 

nised  differences  between  the  great  groups  of  verte- 
brate animals. 

In  Mammals. — In  every  mammal — such  as  the  Dog 
or  Sheep — the  lower  jaw,  which  is  formed  of  one  bone 
on  each  side,  joins  directly  on  to  the  head  of  the 
animal,  and  moves  upon  a  bone  of  the  skull  which 


PTERODACTYLUS  KOCHI  FIG.  2  SKULL   OF    BEAR 

Comparison  to  show  the  articulation  with  the  lower  jaw  in  a  mammal  and 

Pterodactylus  Kochi.     The  quadrate  bone  is  lettered  Q  in  this 

Pterodactyle,  and  comes  between  the  skull  and  the  lower 

jaw  like  the  quadrate  bone  in  a  bird  and  in  lizards 

is  named  the  temporal  bone.  This  character  is 
sufficient  to  prove,  by  the  law  of  association  of  soft 
and  hard  parts  of  the  body,  that  such  an  animal  had 
warm  blood  and  suckled  its  young. 

In  Birds. — In  birds  a  great  difference  is  found  in 
this  region  of  the  head.  The  temporal  bone,  which 
it  will  be  more  convenient  to  name  the  squamosal 
bone,  from  its  squamous  or  scale-like  form,  is  still 
a  part  of  the  brain  case,  and  assists  in  covering  the 
brain  itself,  exactly  as  among  mammals.  But  the 
lower  jaw  is  now  made  up  of  five  or  six  bones.  And 
between  the  hindermost  and  the  squamosal  there  is 
an  intervening  bar  of  bone,  unknown  among  mam- 
malia, which  moves  upon  the  skull  by  a  joint,  just  as 
the  lower  jaw  moves  upon  it.  This  movable  bone 
unites  with  parts  of  the  palate  and  the  face,  and  is 
known  as  the  quadrate  bone.  Its  presence  proves 
that  the  animal  possessing  it  laid  eggs,  and  if  the 


A  REPTILE  IS  KNOWN  BY  ITS  BONES     13 

face  bones  join  its  outer  border  just  above  the  lower 
jaw,  it  proves  that  the  animal  possessed  hot  blood. 

In  Reptiles. — All  reptiles  are  also  regarded  as 
possessing  the  quadrate  bone.  But  the  squamosal 
bone  with  which  it  always  unites  is  in  less  close 
union  with  the  brain  case,  and  never  covers  the  brain 
itself.  Serpents  show  an  extreme  divergence  in  this 
condition  from  birds,  for  the  squamosal  bone  appears 
to  be  a  loose  external  plate  of  bone  which  rests 
upon  the  compact  brain  case  and  gives  attachment 
to  the  quadrate  bone  which  is  as  free  as  in  a  bird. 
Among  Lizards  the  quadrate  bone  is  usually  almost 
as  free.  In  the  other  division  of  existing  Reptilia, 
including  Crocodiles,  the  New  Zealand  lizard-like 
reptile  Hatteria,  called  Tuatera,  and  Turtles,  the 
squamosal  and  quadrate  bones  are  firmly  united  with 
the  bones  of  the  brain  case,  face,  and  palate,  so  that 
the  quadrate  bone  has  no  movement ;  and  the  same 
condition  appears  in  amphibians,  such  as  Toads  and 
Frogs.  With  these  conditions  of  the  quadrate  bone 
are  associated  cold  blood,  terrestrial  life,  and  young 
developed  from  eggs. 

In  Fishes. — Bony  fishes,  and  all  others  in  which 
separate  bones  build  up  the  skull,  differ  from  Rep- 
tiles and  Birds  much  as  those  animals  differ  from 
Mammals.  The  union  of  the  lower  jaw  with  the 
skull  becomes  complicated  by  the  presence  of  addi- 
tional bones.  The  quadrate  bone  still  forms  a  pulley 
articulation  upon  which  the  lower  jaw  works,  but 
between  it  and  the  squamosal  bone  is  the  character- 
istic bone  of  the  fish  known  as  the  hyomandibular, 
commonly  connected  with  opercular  bones  and 
metapterygoid  which  intervene,  and  help  to  unite 
the  quadrate  with  the  brain  case.  In  the  Cartila- 


14  DRAGONS   OF   THE   AIR 

ginous  fishes  there  is  only  one  bone  connecting  the 
jaws  with  the  skull  on  each  side.  This  appears  to 
prove  that  just  as  the  structure  of  the  arch  of  bones 
suspending  the  jaw  may  be  complicated  by  the 
mysterious  process  called  segmentation,  which  sepa- 
rates a  bone  into  portions,  so  simplification  and 
variation  may  result  because  the  primitive  divisions 
of  the  material  cease  to  be  made  which  exists  before 
bones  are  formed. 

The  principal  regions  of  the  skull  and  skeleton  all 
vary  in  the  chief  groups  of  animals  with  backbones ; 
so  that  the  Reptile  may  be  recognised  among  fossils, 
even  in  extinct  groups  of  animals  and  occasionally 
restored  from  a  fragment,  to  the  aspect  which  charac- 
terised it  while  it  lived. 


CHAPTER    IV 
ANIMALS   WHICH    FLY 

THE  nature  of  a  reptile  is  now  sufficiently  in- 
telligible for  something  to  be  said  concerning 
flight,  and  structures  by  means  of  which  some  animals 
lift  themselves  in  the  air.  It  is  not  without  interest 
to  remember  that,  from  the  earliest  periods  in  human 
records,  representations  have  been  made  of  animals 
which  were  furnished  with  wings,  yet  walked  upon 
four  feet,  and  in  their 
typical  aspect  have  the 
head  shaped  like  that  of 
a  bird.  They  are  com- 
monly named  Dragons. 

FLYING    DRAGONS 

The  effigy  of  the 
dragon  survives  to  the 
present  day  in  the  figure 
over  which  St. '  George 
triumphs,  on  the  reverse 
of  the  British  sovereign. 
In  the  luxuriant  imagi- 
nations of  ancient  East- 
ern peoples,  dating  back  From  Tht  Battle**,™  Bel  and  the  Drag** 

'5 


16  DRAGONS   OF   THE   AIR 

to  prehistoric  ages,  perhaps  5000  B.C.,  the  dragons 
present  an  astonishing  constancy  of  form.  In  after- 
times  they  underwent  a  curious  evolution,  as  the  con- 
ception of  Babylon  and  Egypt  is  traced  through 


FIG.  4.      FIGURE   FROM   THE  TEMPLE  OF   EPHESUS 

Assyria  to  Greece.  The  Wings,  which  had  been  asso- 
ciated at  first  with  the  fore  limb  of  the  typical  dragon, 
become  characteristic  of  the  Lion,  and  of  the  poet's 
winged  Horse,  and  finally  of  the  Human  figure  itself, 


ANIMALS   WHICH    FLY  17 

carved  on  the  great  columns  of  the  Greek  temples  of 
Ephesus.  These  flying  animals  are  historically  de- 
scendants of  the  same  common  stock  with  the  dragons 
of  China  and  Japan,  which  still  preserve  the  aspect 
of  reptiles.  Their  interest  is  chiefly  in  evidence  of 
a  latent  spirit  of  evolution  in  days  too  remote  for  its 
meaning  to  be  now  understood,  which  has  carried  the 
winged  forms  higher  and  ever  higher  in  grade  of 
organisation,  till  their  wings  ceased  to  be  associated 
with  feelings  of  terror.  The  Hebrew  cherubim  are 
regarded  by  H.  E.  Ryle,  Bishop  of  Exeter,  as  prob- 
ably Dragons,  and  the  figure  of  the  conventional 
angel  is  the  human  form  of  the  Dragon. 

ORGANS    OF   FLIGHT 

Turning  from  this  reference  to  the  realm  of  myth- 
ology to  existing  nature,  the  power  of  flight  is 
popularly  associated  with  all  the  chief  types  of 
vertebrate  animals — fishes,  frogs,  lizards,  birds,  and 
mammals.  Many  of  the  animals  ill  deserve  the 
name  of  flyers,  and  most  are  exceptions  to  different 
conditions  of  existence  which  control  their  kindred, 
but  it  is  convenient  to  examine  for  a  little  the  nature 
of  the  structures  by  which  this  movement  in  the  air, 
which  is  not  always  flight,  is  made  possible.  Certain 
fishes,  like  the  lung-fish  Ceratodus,  of  Queensland, 
and  the  mud-fish  Lepidosiren,  are  capable  of  leaving 
the  water  and  living  on  land,  and  for  a  time  breathe 
air.  But  neither  these  fishes  nor  Periophthalmus, 
which  runs  with  rapid  movement  of  its  fins  and 
carries  the  body  more  or  less  out  of  water,  or  the 
climbing  perch,  Anabas,  carried  out  of  water  over 
the  country  by  Indian  jugglers,  ever  put  on  the 
slightest  approach  to  wings. 


18  DRAGONS   OF   THE   AIR 

FLYING    FISHES 

The  flight  of  fishes  is  a  kind  of  parachute  support 
not  unlike  that  by  which  a  folded  paper  is  made  to 
travel  in  the  air.  It  is  chiefly  seen  in  the  numerous 
species  of  a  genus  Exocoetus,  allied  to  the  gar-pike 


FIG.  5.    THE  FLYING  FISH  EXOCCETUS 
With  the  fins  extended  moving  through  the  air 

(Belone),  which  is  common  in  tropical  seas,  and 
usually  from  a  foot  to  eighteen  inches  long.  They 
emerge  from  the  water,  and  for  a  time  support  them- 
selves in  the  air  by  means  of  the  greatly  developed 
breast  fins,  which  sometimes  extend  backward  to  the 
tail  fin.  Although  these  fins  appear  to  correspond 
to  the  fore  limbs  of  other  animals,  they  may  not 
be  moved  at  the  will  of  the  fish  like  the  wing  of  a 
bird.  When  the  flying  fishes  are  seen  in  shoals  in 
the  vicinity  of  ships,  those  fins  remain  extended,  so 
that  the  fish  is  said  sometimes  to  travel  200  yards 
at  a  speed  of  fifteen  miles  an  hour,  rising  twenty  feet 
or  more  above  the  surface  of  the  sea,  travelling  in 
a  straight  line,  though  sometimes  influenced  by  the 
wind.  Here  the  organ,  which  is  at  once  a  fin  and  a 


ANIMALS   WHICH    FLY  19 

wing,  consists  of  a  number  of  thin  long  rods,  or  rays, 
which  are  connected  by  membrane,  and  vary  in 
length  to  form  an  outline  not  unlike  the  wing  of  a 
bird  which  tapers  to  a  point.  The  interest  of  these 
animals  is  chiefly  in  the  fact  that  flight  is  separated 
from  the  condition  of  having  lungs  with  which  it 
is  associated  in  birds,  for  although  the  flying  fish  has 
an  air  bladder,  there  is  no  duct  to  connect  it  with 
the  throat. 

FLYING    FROGS 

Among  amphibians  the  organs  of  flight  are  also 
of  a  parachute  kind,  but  of  a  different  nature.  They 
are  seen  in  certain  frogs  which 
frequent  trees,  and  are  limited 
to  membranes  which  extend 
between  the  diverging  digits 
of  the  hand  and  foot,  forming 
webs  as  fully  developed  as  in 
the  foot  of  a  swimming  bird. 
As  these  frogs  leap,  the  mem- 
branes are  expanded  and  help 
to  support  the  weight  of  the 

.        .     r  .  ,  •          ,      i  FIG.  6.      THE  FLYING   FROG 

body,  so  that  the  animal  de-  (RHACOPHORUS) 

SCCnds  more  easily  as  it  mOVeS  The   membranes  of  the  foot  and 

-             ,               ,            ,                ,             ,  hand  extend  between  the  metatarsal 

from  branch  tO  branch.     There  and  metacarpal  bones,  as  well  as  the 

•  I                  .             -         .  bones  of  the  digits. 

is  no  evidence  that  the  bones 

of  the  digits  ever  became  elongated  like  the  fin  rays 
of  the  flying  fish  or  the  wing  bones  of  a  Bat ;  but 
the  web  suggests  the  basis  of  such  a  wing,  and  the 
possibilities  under  which  wings  may  first  originate, 
by  elongation  of  the  bones  of  a  webbed  hand  like 
that  of  a  Flying  Frog. 


20  DRAGONS   OF   THE   AIR 

FLYING   LIZARDS 

The  Reptilia  in  their  several  orders  are  remarkable 
for  absence  of  any  modification  of  the  arms  which 
might  suggest  a  capacity  for  acquiring  wings,  as 
being  latent  in  their  organisation.  Crocodiles,  Tor- 
toises, and  Serpents  are  alike  of  the  earth,  and  not 
of  the  air.  But  among  Lizards  there  are  small  groups 


FIG.  7.      THE   FLYING   DRAGON,    DRACO 
Forming  a  parachute  by  means  of  the  extended  ribs 

of  animals  in  which  a  limited  capacity  for 
movement   through  the  air  is  developed. 
It  is  best  known  in  the  family  of  small 
lizards  named  Dragons,  represented  typic- 
ally by  the  species  Draco  volans  found  in  the  Oriental 
region  of  the  East  Indies  and  Malay  Archipelago. 

The  organ  of  flight  is  produced  in  an  unexpected 
way,  by  means  of  the  ribs  instead  of  the  limbs.  The 
ribs  extend  outward  as  far  as  the  arms  can  stretch, 
and  the  first  five  or  six  are  prolonged  beyond  the 
body  so  as  to  spread  a  fold  of  skin  on  each  side 
between  the  arm  and  the  leg.  The  membrane  admits 


ANIMALS   WHICH    FLY  21 

of  some  movement  with  the  ribs.  This  arrangement 
forms  a  parachute,  which  enables  the  animal  to  move 
rapidly  among  branches  of  trees,  extending  the  struc- 
ture at  will,  so  that  it  is  used  with  rapidity  too  quick 
to  be  followed  by  the  eye,  as  it  leaps  through  consider- 
able distances. 

A  less  singular  aid  to  movement  in  the  air  is  found 
in  some  of  the  lizards  termed  Geckos.  The  so-called 
Flying  Gecko  {Platydactylus  homalocephalus]  has  a 
fringe  unconnected  with  ribs,  which  extends  laterally 
on  the  sides  of  the  body  and  tail,  as  well  as  at  the 
back  and  front  of  the  fore  and  hind  limbs,  and  be- 
tween the  digits,  where  the  web  is  sometimes  almost  as 
well  developed  as  among  Tree  Frogs.  This  is  essen- 
tially a  lateral  horizontal  frill,  extending  round  the 
body.  Its  chief  interest  is  in  the  circumstance  that  it 
includes  a  membrane  which  extends  between  the  wrist 
bones  and  the  shoulder  on  the  front  of  the  arm.  That 
is  the  only  part  of  the  fringe  which  represents  the  wing 
membrane  of  a  bird.  The  fossil  flying  reptiles  have 
not  only  that  membrane,  but  the  lateral  membranes 
at  the  sides  of  the  body  and  behind  the  arms. 

Other  lizards  have  the  skin  developed  in  the 
direction  of  the  circumference  of  the  body.  In  the 
Australian  Chlamydosaurus  it  forms  an  immense 
frill  round  the  neck  like  a  mediaeval  collar.  But 
though  such  an  adornment  might  break  a  fall,  it 
could  not  be  regarded  as  an  organ  of  flight. 

FLYING  BIRDS 

The  wings  of  birds,  when  they  are  developed  so  as 
to  minister  to  flight,  are  all  made  upon  one  plan  ;  but 
as  examples  of  the  variation  which  the  organs  con- 
tributing to  make  the  fore  limb  manifest,  I  may 


22 


DRAGONS   OF  THE   AIR 


instance  the  short  swimming  limb  of  the  Penguin, 
the  practically  useless  rudiment  of  a  wing  found  in 
the  Ostrich  or  Kiwi,  and  the  fully  developed  wing  of 
the  Pigeon.  The  wings  of  birds  obtain  an  extensive 
surface  to  support  the  animal  by  muscular  movements 


FIG.  8.      POSITION   OF   BIRDS   IN    FLIGHT 

of  three  modifications  of  structure.  First,  the  bones 
of  the  fore  limb  are  so  shaped  that  they  cannot,  in 
existing  birds,  be  applied  to  the  ground  for  support 
and  be  used  like  the  limbs  of  quadrupeds,  and  are 
therefore  folded  up  at  the  sides  of  the  body,  and 


ANIMALS  WHICH    FLY  23 

carried  in  an  unused  or  useless  state  so  long  as  the 
animal  hops  on  the  ground  or  walks,  balancing  its 
weight  on  the  hind  legs.  Secondly,  there  are  two 
small  folds  of  skin,  less  conspicuous  than  those  on 
the  arms  of  Geckos ;  one  is  between  the  wrist  bones 
and  the  shoulder,  and  the  smaller  hinder  membrane 
is  between  the  upper  arm  and  the  body.  These 
membranous  expansions  are  insignificant,  and  would 
in  themselves  be  inadequate  to  support  the  body  or 
materially  assist  its  movements.  Thirdly,  the  bird 
develops  appendages  to  the  skin  which  are  familiarly 
known  as  feathers,  and  the  large  feathers  which  make 
the  wing  are  attached  to  the  skin  covering  the  lower 
arm  bone  named  the  ulna,  and  the  other  bones  which 
represent  the  wrist  and  hand.  The  area  and  form  of 
the  bird's  wing  are  due  to  individual  appendages  to 
the  skin,  which  are  unknown  in  any  other  group  of 
animals.  Between  the  extended  wing  of  the  Alba- 
tross, measuring  eleven  feet  in  spread,  and  the  con- 
dition in  the  Kiwi  of  New  Zealand,  in  which  the 
wing  is  vanishing,  there  is  every  possible  variation  in 
size  and  form.  As  a  rule,  the  larger  the  animal  the 
smaller  is  the  wing  area.  The  problem  of  the  origin 
of  the  bird's  wing  is  not  to  be  explained  by  study  of 
existing  animals;  for  the  rowing  organ  of  the  Pen- 
guin, which  in  itself  would  never  suggest  flight, 
becomes  an  organ  of  flight  in  other  birds  by  the 
growth  upon  it  of  suitable  feathers.  Anyone  who 
has  seen  the  birds  named  Divers  feeding  under  water, 
swimming  rapidly  with  their  wings,  might  never 
suspect  that  they  were  also  organs  of  aerial  flight. 
The  Ostrich  is  even  more  interesting,  for  it  has  not 
developed  flight,  and  still  retains  at  the  extremities 
of  two  of  the  digits  the  slender  claws  of  a  limb 


24  DRAGONS   OF   THE   AIR 

which  was  originally  no  wing  at  all,  but  the  support 
of  a  four-footed  animal  (Fig.  46,  p.  130). 

FLYING    MAMMALS 

Flight  is  also  developed  among  mammals.  The 
Insectivora  include  several  interesting  examples  of 
animals  which  are  capable  of  a  certain  motion  through 
the  air.  In  the  tropical  forests  of  the  Malay  Archi- 
pelago are  animals  known  as  Flying  Squirrels,  Flying 
p.  Opossums,  Flying  Lemurs,  Flying 

,'     I  Foxes,  in  which  the  skin  extends 

'>  outward  laterally  from  the  sides 

/f^     of  the  body  so  as  to  connect  the 
'       \         fore  limbs  with  the  hind  limbs, 
;        j     \       V        and  is  also  prolonged  backward 
5  ]        \      from  the  hind  limbs  to  the  tail. 

',  }  \  The  four  digits  are  never  elon- 
gated ;  the  bones  of  the  fore  limb 
are  neither  longer  nor  larger  than 
those  of  the  hind  limb,  and  the 

FIG.  Q.      FLYING  r       .  .  •       c          v.^1          i 

SQUIRREL  (PTEROMYS)  foot  terminates  in  five  little  claws 
as  in  other  four-footed  animals. 
This  condition  is  adapted  for  the  arboreal  life  which 
those  animals  live,  leaping  from  branch  to  branch, 
feeding  on  fruits  and  leaves,  and  in  some  cases 
upon  insects.  These  mammals  may  be  compared 
with  the  Flying  Geckos  among  reptiles  in  their 
parachute-like  support  by  extension  of  the  skin, 
which  gives  them  one  of  the  conditions  of  support 
which  contribute  to  constitute  flight. 

Bats. — One  entire  order  of  mammals — the  Bats — 
not  only  possess  true  wings,  but  are  capable  of  flight 
which  is  sustained,  and  in  some  cases  powerful.  The 
wings  are  clothed  with  short  hair  like  the  rest  of  the 


ANIMALS   WHICH    FLY  25 

body,  and  thus  the  instrument  of  flight  is  unlike  that 
of  a  bird.  The  flight  of  a  Bat  differs  from  that 
of  all  other  animals  in  being  dependent  upon  a 
modification  of  the  bones  of  the  fore  limb,  which, 
without  interfering  with  the  animal's  movements  as 
a  quadruped,  secures  an  extension  of  the  wing  which 
is  not  inferior  in  area  to  that  which  the  bird  obtains 


FIG.   10 
NEW   ZEALAND   BAT   FLYING.      BARBASTELLE   WALKING 

by  elongation  of  the  bones  of  the  arm  and  fore-arm 
and  its  feathers.  The  distinctive  peculiarity  of  the 
Bat's  wing  is  in  the  circumstance  that  four  of  the 
digits  of  the  hand  have  their  bones  prolonged  to 
a  length  which  is  often  equal  to  the  combined  length 
of  the  arm  and  fore-arm.  The  bones  of  the  digits 


26  DRAGONS   OF  THE   AIR 

diverge  like  the  ribs  of  an  umbrella,  and  between 
them  is  the  wing  membrane,  which  extends  from  the 
sides  of  the  body  outward,  unites  the  fore  limb  with 
the  hind  limb,  and  is  prolonged  down  the  tail  as 
in  the  Flying  Foxes.  Bats  have  a  small  membrane 
in  front  of  the  bones  of  the  arm  and  fore-arm 
stretching  between  the  shoulder  and  the  wrist,  which 
corresponds  with  the  wing  membrane  of  a  bird  ;  but 
the  remainder  of  the  membranes  in  Bats'  wings  are 
absent  in  birds,  because  their  function  is  performed 
by  feathers  which  give  the  wing  its  area.  The 
elongated  digits  of  the  Bat's  wing  are  folded  together 
and  carried  at  the  sides  of  the  body  as  though  they 
were  a  few  quill  pens  attached  to  its  wrist,  where  the 
one  digit,  which  is  applied  to  the  ground  in  walking, 
terminates  in  a  claw. 

The  organs  which  support  animals  in  the  air  are 
thus  seen  to  be  more  or  less  dissimilar  in  each  of  the 
great  groups  of  animals.  They  fall  into  three  chief 
types :  first,  the  parachute ;  secondly,  the  wing  due 
to  the  feathers  appended  to  the  skin ;  and  thirdly,  the 
wing  formed  of  membrane,  supported  by  enormous 
elongation  of  the  small  bones  of  the  back  of  the 
hand  and  fingers.  The  two  types  of  true  wings  are 
limited  to  birds  and  bats ;  and  no  living  reptile 
approximates  to  developing  such  an  organ  of  flight 
as  a  wing.  Judged,  therefore,  by  the  method  of  com- 
paring the  anatomical  structures  of  one  animal  with 
another,  which  is  termed  "  comparative  anatomy,"  the 
existence  of  flying  reptiles  might  be  pronounced 
impossible.  But  in  the  light  which  the  revelations 
of  geology  afford,  our  convictions  become  tempered 
with  modesty  ;  and  we  learn  that  with  Nature  nothing 
is  impossible  in  development  of  animal  structure. 


CHAPTER  V 

DISCOVERY    OF    THE 
PTERODACTYLE 


EiTE  in  the  eighteenth  century,  in  1784,  a  small 
fossil  animal  with  wings  began  to  be  known 
through  the  writings  of  Collini,  as  found  in  the  white 
lithographic  limestone  of  Solenhofen  in  Bavaria,  and 
was  regarded  by  him  as  a  former  inhabitant  of  the 
sea.  The  foremost  naturalist  of  the  time,  the  citizen 
Cuvier  —  for  it  was  in  the  days  of  the  French  Republic 
—  in  i8oi,in  lucid  language,  interpreted  the  animal  as 
a  genus  of  Saurians.  That  word,  so  familiar  at  the 
present  day,  was  used  in  the  first  half  of  the  century 
to  include  Lizards  and  Crocodiles  ;  and  described 
animals  akin  to  reptiles  which  were  manifestly  re- 
lated neither  to  Serpents  nor  Turtles.  But  the  term 
saurian  is  no  longer  in  favour,  and  has  faded  from 
science,  and  is  interesting  only  in  ancient  history  of 
progress.  The  lizards  soon  became  classed  in  close 
alliance  with  snakes.  And  the  crocodiles,  with  the 
Hatteria,  were  united  with  chelonians.  Most  modern 
naturalists  who  use  the  term  saurian  still  make  it 
an  equivalent  of  lizard,  or  an  animal  of  the  lizard 
kind. 

27 


28  DRAGONS   OF   THE   AIR 

CUVIER 

Cuvier  defined  this  fossil  from  Solenhofen  as  dis- 
tinguished by  the  extreme  elongation  of  the  fourth 
digit  of  the  hand,  and  from  that  character  invented 
for  the  animal  the  name  Pterodactyle.  He  tells  us 


FIG.    II.       PTERODACTYLUS  LONGIROSTRIS  (Cuvier) 

The  remains  are  preserved  with  the  neck  arched  over  the  back,  and  the  jaws 

opened  upward 

that  its  flight  was  not  due  to  prolongation  of  the  ribs, 
as  among  the  living  lizards  named  Dragons ;  or  to  a 
wing  formed  without  the  digits  being  distinguishable 
from  each  other,  as  among  Birds ;  nor  with  only  one 
digit  free  from  the  wing,  as  among  Bats  ;  but  by 


DISCOVERY  OF  THE  PTERODACTYLE    29 

having  the  wing  supported  mainly  by  a  single  greatly 
elongated  digit,  while  all  the  others  are  short  and 
terminate  in  claws.  Cuvier  described  the  amazing 
animal  in  detail,  part  by  part ;  and  such  has  been  the 
influence  of  his  clear  words  and  fame  as  a  great 
anatomist  that  nearly  every  writer  in  after -years, 
in  French  and  in  English,  repeated  Cuvier's  con- 


no.   12.      THE  SKELETON   OF  PTERODACTYLVS  LONG1ROSTRIS 

Reconstructed  from  the  scattered  bones  in  Fig.  14,  showing  the  limbs 

on  the  left  side 

elusion,  maintained  to  the  end,  that  the  animal  is  a 
saurian. 

Long  before  fashion  determined,  as  an  article  of 
educated  belief,  that  fossil  animals  exist  chiefly  to 
bridge  over  the  gaps  between  those  which  still  sur- 
vive, the  scientific  men  of  Germany  were  inclined  to 
see  in  the  Pterodactyle  such  an  intermediate  type 
of  life.  At  first  Sommerring  and  Wagler  would 
have  placed  the  Pterodactyle  between  mammals 
and  birds. 


30  DRAGONS   OF   THE   AIR 

GOLDFUSS 

But  the  accomplished  naturalist  Goldfuss,  who 
described  another  fine  skeleton  of  a  Pterodactyle 
in  1831,  saw  in  this  flying  animal  an  indication  of 
the  course  taken  by  Nature  in  changing  the  reptilian 
organisation  to  that  of  birds  and  mammals.  It  is 
the  first  flash  of  light  on  a  dark  problem,  and  its 
brilliance  of  inference  has  never  been  equalled.  Its 


FIG.    13.       THE   PTERODACTYLUS  I.ONGIROSTRIS   RESTORED 

FROM  THE   REMAINS   IN   FIG.   II 
Showing  positions  of  the  wing  membranes  with  the  animal  at  rest 

effects  were  seen  when  Prince  Charles  Bonaparte, 
the  eminent  ornithologist,  in  Italy,  suggested  for  the 
group  the  name  Ornithosauria ;  when  the  profound 
anatomist  de  Blainville,  in  France,  placed  the  short- 
tailed  animal  in  a  class  between  Reptiles  and  Birds 
named  Pterodactylia ;  and  Andreas  Wagner,  of 
Munich,  who  had  more  Pterodactyles  to  judge  from 


DISCOVERY  OF  THE  PTERODACTYLE     31 

than    his    predecessors,  saw   in    the   fossil   animal   a 
saurian  in  transition  to  a  bird. 

VON    MEYER 

But  the  German  interpretation  is  not  uniform, 
and  Hermann  von  Meyer,  the  banker-naturalist  of 
Frankfurt  a./M.,  who  made  himself  conversant  with 
all  that  his  predecessors  knew,  and  enlarged  know- 
ledge of  the  Pterodactyles  on  the  most  critical  facts 
of  structure,  continued  to  regard  them  as  true  reptiles, 
but  flying  reptiles.  Such  is  the  influence  of  von 
Meyer  that  all  parts  of  the  world  have  shown  a 
disposition  to  reflect  his  opinions,  especially  as  they 
practically  coincide  with  the  earlier  teaching  of 
Cuvier.  Owen  and  Huxley  in  England,  Cope  and 
Marsh  in  America,  Gaudry  in  France,  and  Zittel  in 
Germany  have  all  placed  the  Pterodactyles  as  flying 
reptiles.  Their  judgment  is  emphatic.  But  there  is 
weight  of  competent  opinion  to  endorse  the  evolu- 
tionary teaching  of  Goldfuss  that  they  rise  above 
reptiles.  To  form  an  independent  opinion  the  modern 
student  must  examine  the  animals,  weigh  their  char- 
acters bone  by  bone,  familiarise  himself,  if  possible, 
with  some  of  the  rocks  in  which  they  are  found  ; 
to  comprehend  the  conditions  under  which  the  fossils 
are  preserved,  which  have  added  not  a  little  to  the 
interest  in  Pterodactyles,  and  to  the  difficulty  of 
interpretation. 

GEOLOGICAL   HISTORY   OF   PTERODACTYLES   IN 
GERMANY 

We  may  briefly  recapitulate  the  geological  history. 
Those  remains  of  Ornithosaurs  which  have  been  men- 
tioned, with  a  multitude  of  others  which  are  the  glory 


32  DRAGONS   OF   THE   AIR 

of  the  museums  of  Munich,  Stuttgart,  Tubingen, 
Heidelberg,  Bonn,  Haarlem,  and  London,  have  all 
been  found  in  working  the  lithographic  stone  of 
Bavaria.  The  whitish  yellow  limestone  forms  low, 
flat-topped  hills,  now  isolated  from  each  other  by 
natural  denudation,  which  has  removed  the  inter- 
vening rock.  The  stone  is  found  at  some  distance 
north  of  the  Danube,  in  a  line  due  north  of  Augsburg, 
in  the  country  about  Pappenheim,  and  especially  at 
the  villages  of  Solenhofen,  Eichstadt,  Kelheim,  and 
Nusplingen.  These  beds  belong  to  the  rocks  which 
are  named  White  Jura  limestone  in  Germany,  which 
is  of  about  the  same  geological  age  as  the  Kimeridge 
clay  in  England.  Much  of  it  divides  into  very  thin 
layers,  and  in  these  planes  of  separation  the  fossils 
are  found.  They  include  the  Ammonites  litho- 
graphicus  and  a  multitude  of  marine  shells,  king 
crabs  and  other  Crustacea,  sea-urchins,  and  other 
fossils,  showing  that  the  deposit  was  formed  in  the 
sea.  The  preservation  of  jelly-fish,  which  so  soon 
disappear  when  left  dry  on  the  beach,  shows  that  the 
ancient  calcareous  mud  had  unusual  power  of  pre- 
serving fossils.  Into  this  sea,  with  its  fishes  great 
and  small,  came  land  plants  from  off  the  land,  dragon- 
flies  and  other  insects,  tortoises  and  lizards,  Ptero- 
dactyles  with  their  flying  organs,  and  birds  still 
clothed  with  feathers.  Sometimes  the  wing  mem- 
branes of  the  flying  reptiles  are  found  fully  stretched 
by  the  wing  finger,  as  in  examples  to  be  seen  at 
Munich  and  in  the  Yale  Museum  in  Newhaven,  in 
America.  At  Haarlem  there  is  an  example  in  which 
the  wing  membrane  appears  to  be  folded  much  as  in 
the  wing  of  a  Bat,  when  the  animal  hangs  suspended, 
with  the  flying  membrane  bent  into  a  few  wide  un- 
dulations. 


DISCOVERY  OF  THE  PTERODACTYLE    33 

The  Solenhofen  Slate  belongs  to  about  the  middle 
period  of  the  history  of  flying  reptiles,  for  they 
range  through  the  Secondary  epochs  of  geological 
time.  Remains  are  recorded  in  Germany  from  the 
Keuper  beds  at  the  top  of  the  Trias,  which  is  the 
bottom  division  of  the  Secondary  strata ;  and  I  be- 
lieve I  have  seen  fragments  of  their  bones  from 
the  somewhat  older  Muschelkalk  of  Germany. 

THEIR  HISTORY  IN  ENGLAND 
In  England  the  remains  are  found  for  the  first  time 
in  the  Lower  Lias  of  Lyme  Regis,  in  Dorset,  and  the 
Upper  Lias  of  Whitby,  in  Yorkshire.  In  Wurtemberg 
they  occur  on  the  same  horizons.  They  reappear  in 
England,  in  every  subsequent  age,  when  the  condi- 
tions of  the  strata  and  their  fossils  give  evidence  of 
near  proximity  to  land.  In  the  Stonesfield  Slate  of 
Stonesfield,  in  Oxfordshire,  the  bones  are  found 
isolated,  but  indicate  animals  of  some  size,  though 
not  so  large  as  the  rare  bones  of  reputed  true 
birds  which  appear  to  have  left  their  remains  in 
the  same  deposit. 

At  least  two  Pterodactyles  are  found  in  the  Oxford 
clay,  known  from  more  or  less  fragmentary  remains  or 
isolated  bones ;  just  as  they  occur  in  the  Kimeridge 
Clay,  Purbeck  Limestone,  Wealden  sandstones,  and 
especially  in  newer  Secondary  rocks,  named  Gault, 
Upper  Greensand,  and  Chalk,  in  the  south-east  of 
England. 

Owing  to  exceptional  facilities  for  collecting,  in 
consequence  of  the  Cambridge  Greensand  being 
excavated  for  the  valuable  mineral  phosphate  of 
lime  it  contains,  more  than  a  thousand  bones  are 
preserved,  more  or  less  broken  and  battered,  in  the 


34  DRAGONS   OF   THE   AIR 

Wood  ward  ian  Museum  of  the  University  of  Cam- 
bridge alone.  To  give  some  idea  of  their  abundance, 
it  may  be  stated  that  they  were  mostly  gathered 
during  two  or  three  years,  as  a  matter  of  business, 
by  an  intelligent  foreman  of  washers  of  the  nodules 
of  phosphate  of  lime,  which,  in  commerce,  are  named 
coprolites.  He  soon  learned  to  distinguish  Ptero- 
dactyle  bones  from  other  fossils  by  their  texture,  and 
learned  the  anatomical  names  of  bones  from  speci- 
mens in  the  University  Museum.  This  workman, 
Mr.  Pond,  employed  by  Mr.  William  Farren,  brought 
together  not  only  the  best  of  the  remains  at  Cam- 
bridge, but  most  of  those  in  the  museums  at  York 
and  in  London,  and  the  thousands  of  less  perfect 
specimens  in  public  and  private  collections  which 
passed  through  the  present  writer's  hands  in  en- 
deavours to  secure  for  the  University  useful  illustra- 
tions of  the  animal's  structure.  These  fragments, 
among  which  there  are  few  entire  bones,  are  valu- 
able, for  they  have  afforded  opportunities  of  examin- 
ing the  articular  ends  of  bones  in  every  aspect,  which 
is  not  possible  when  similar  organic  remains  are  em- 
bedded in  rock  in  their  natural  connexions. 

In  England  Flying  Reptiles  disappear  with  the 
Chalk.  In  that  period  they  were  widely  distributed, 
being  found  in  Bohemia,  in  Brazil,  and  Kansas  in  the 
United  States,  as  well  as  in  Kent  and  other  parts  of 
England.  They  attained  their  largest  dimensions  in 
this  period  of  geological  time.  One  imperfect  frag- 
ment of  a  bone  from  the  Laramie  rocks  of  Canada 
was  described,  I  believe,  by  Cope,  though  not  identi- 
fied by  him  as  Ornithosaurian,  and  is  probably  newer 
than  other  remains. 


DISCOVERY  OF  THE  PTERODACTYLE    35 

ASPECT   OF  PTERODACTYLES 

If  this  series  of  animals  could  all  be  brought 
together  they  would  vary  greatly  in  aspect  and 
stature,  as  well  as  in  structure.  Some  have  the  head 
enormously  long,  in  others  it  is  large  and  deep, 
characters  which  are  shared  by  extinct  reptiles  which 
do  not  fly,  and  to  which  some  birds  may  approxi- 
mate ;  while  in  a  few  the  head  is  small  and  compact, 
no  more  conspicuous,  relatively,  than  the  head  of 
a  Sparrow.  The  neck  may  be  slender  like  that  of 
a  Heron,  or  strong  like  that  of  an  Eagle;  the  back  is 
always  short,  and  the  tail  may  be  inconspicuous,  or 
as  long  as  the  back  and  neck  together.  These  flying 
reptiles  frequently  have  the  proportions  of  the  limbs 
similar  to  those  of  a  Bat,  with  fore  legs  strong  and 
hind  legs  relatively  small ;  while  in  some  the  limbs 
are  as  long,  proportionately,  and  graceful  as  those  of 
a  Deer.  With  these  differences  in  proportions  of  the 
body  are  associated  great  differences  in  the  relative 
length  of  the  wing  and  spread  of  the  wing  membranes. 

DIMENSIONS   OF   THE   ANIMALS 

The  dimensions  of  the  animals  have  probably 
varied  in  all  periods  of  geological  time.  The 
smallest,  in  the  Lithographic  Slate,  are  smaller  than 
Sparrows,  while  associated  with  them  are  others  in 
xvhich  the  drumstick  bone  of  the  leg  is  eight  inches 
long.  In  the  Cambridge  Greensand  and  Chalk  im- 
perfect specimens  occur,  showing  that  the  upper  arm 
bones  are  larger  than  those  of  an  Ox.  The  shaft  is 
one  and  a  half  inches  in  diameter  and  the  ends  three 
inches  wide.  Such  remains  may  indicate  Pterodac- 
tyles  not  inferior  in  size  to  the  extinct  Moas  of 


36  DRAGONS   OF  THE   AIR 

New    Zealand,   but    with    immensely   larger  heads, 
animals  far  larger  than  birds  of  flight 

The  late  Sir  Richard  Owen,  on  first  seeing  these 
fragmentary  remains,  said  "  the  flying  reptile  with 
outstretched  pinions  must  have  appeared  like  the 
soaring  Roc  of  Arabian  romance,  but  with  the  fea- 
tures of  leathern  wings  with  crooked  claws  super- 
induced, and  gaping  mouth  with  threatening  teeth." 
Eventually  we  shall  obtain  more  exact  ideas  of  their 
aspect,  when  the  structures  of  the  several  regions  of 
the  body  have  been  examined.  The  great  dimen- 
sions of  the  stretch  of  wing,  often  computed  at 
twenty  feet  in  the  larger  examples,  might  lead  to 
expectations  of  great  weight  of  body,  if  it  were  not 
known  that  an  albatross,  with  wings  spreading 
eleven  feet,  only  weighs  about  seventeen  pounds. 


CHAPTER  VI 

HOW  ANIMALS  ARE  INTERPRETED 
BY  THEIR  BONES 

THERE  is  only  one  safe  path  which  the  natural- 
ist may  follow  who  would  tell -the  story  of  the 
meaning  and  nature  of  an  extinct  type  of  animal 
life,  and  that  is  to  compare  it  as  fully  as  possible  in 
its  several  bones,  and  as  a  whole,  with  other  animals, 
especially  with  those  which  survive.  It  is  easy  to 
fix  the  place  in  nature  of  living  animals  and  deter- 
mine their  mutual  relations  to  each  other,  because  all 
the  organs — vital  as  well  as  locomotive — are  avail- 
able for  comparison.  On  such  evidence  they  are 
grouped  together  into  the  large  divisions  of  Beasts, 
Birds,  and  Reptiles ;  as  well  as  placed  in  smaller 
divisions  termed  Orders,  which  ar«e  based  upon  less 
important  modifications  of  fundamental  structures. 
All  these  characteristic  organs  have  usually  dis- 
appeared in  the  fossil.  Hence  a  new  method  of 
study  of  the  hard  parts  of  the  skeleton,  which  alone 
are  preserved,  is  used  in  the  endeavour  to  discover 
how  the  Flying  Reptile  or  other  extinct  animal  is  to 
be  classified,  and  how  it  acquired  its  characters  or 
came  into  existence. 


38  DRAGONS   OF   THE   AIR 

VARIATIONS  OF  BONES  AMONG  MAMMALIA 
Resemblances  and  differences  in  the  bones  are 
easily  over-estimated  in  importance  as  evidence  of 
pedigree  relationship.  The  Mammalia  show,  by 
means  of  such  skeletons  as  are  exhibited  in  any 
Natural  History  Museum,  how  small  is  the  import- 
ance to  be  attached  to  even  the  existence  of  any 
group  of  bones  in  determining  its  grade  of  organisa- 

Mole  Giraffe  Bat  Porpoise 


Burrowing        Running  Flying  Swimming 

FIG.   14.      THE   FORE   LIMU    IN    FOUR   TYPES   OF   MAMMALS 

Comparison  of  the  Fore  limb  in  mammals,  showing  variation 
of  form  of  the  bones  with  function 

tion.  The  whole  Whale  tribe  suckle  their  young  and 
conform  to  the  distinctive  characters  in  brain  and 
lungs  which  mark  them  as  being  mammals.  But  if 
there  is  one  part  of  the  skeleton  more  than  another 
which  distinguishes  the  Mammalia,  it  is  the  girdle  of 
bones  at  the  hips  which  supports  the  hind  limbs.  It 
is  characterised  by  the  bone  named  the  ilium  being 


ANIMALS  KNOWN  BY  THEIR  BONES    39 

uniformly  directed  forward.  Yet  in  the  Whale  tribe 
the  hip-girdle  and  the  hind  limb  which  it  usually 
supports  are  so  faintly  indicated  as  to  be  practically 
lost;  while  the  fore  limb  becomes  a  paddle  without 
distinction  of  digits,  and  is  therefore  devoid  of  hoofs 
or  claws,  which  are  usual  terminations  of  the  extremi- 
ties in  mammals.  Yet  this  swimming  paddle,  with 
its  ill-defined  bones — sometimes  astonishing  in  num- 
ber, as  well  as  in  fewness  of  the  finger  bones — is 
represented  by  the  burrowing  fore  limb  of  the  Mole, 
which  lives  underground;  by  the  elongated  hoofed 
legs  of  the  Giraffe,  which  lives  on  plains ;  and  the 
extended  arm  and  finger  bones  of  the  Bat,  which  are 
equally  mammals  with  the  Whale.  From  such  com- 
parison it  is  seen  that  no  proportion,  or  form,  or 
length,  or  use  of  the  bones  of  the  limbs,  or  even  the 
presence  of  limbs,  is  necessarily  characteristic  of  a 
mammal.  No  limitation  can  be  placed  upon  the 
possible  diversity  of  form  or  development  of  bones 
in  unknown  animals,  when  they  are  considered  in  the 
light  of  such  experience  of  varied  structural  condi- 
tions in  living  members  of  a  single  class. 

What  is  true  for  the  limbs  and  the  bony  arches 
which  support  them  is  true  for  the  backbone  also,  for 
the  ribs,  and  to  some  extent  for  the  skull.  The  neck 
in  the  Whale  is  shortened  almost  beyond  recognition. 
In  the  Giraffe  the  same  seven  vertebrae  are  elongated 
into  a  marvellous  neck ;  so  that  in  the  technical 
definition  of  a  mammal  both  are  said  to  have  seven 
neck  vertebras.  Yet  exceptions  show  a  capacity  for 
variation.  One  of  the  Sloths  reduces  the  number  to 
six,  while  another  has  nine  vertebrae  in  the  neck ; 
proving  that  there  is  no  necessary  difference  between 
a  mammal  and  a  reptile  when  judged  by  a  character 


40  DRAGONS   OF   THE  AIR 

which  is  typically  so  distinctive  of  mammals  as  the 
number  of  the  neck  bones. 

The  skull  varies  too,  though  to  a  less  extent.  The 
Great  Ant-eater  of  South  America  is  a  mammal  abso- 
lutely without  teeth.  The  Porpoises  have  a  simple 
unvarying  row  of  conical  teeth  with  single  roots  ex- 
tending along  the  jaw.  And  the  dental  armature  of 
the  jaws,  and  relative  dimensions  of  the  skull  bones, 
exhibit  such  diversity,  in  evidence  of  what  may  be 
parted  with  or  acquired,  that  recognition  of  the  many 
reptilian  structures  and  bones  in  the  skull  of  Orni- 
thorhynchus,  the  Australian  Duckbill,  demonstrates 
that  the  difficulties  in  recognising  an  animal  by  its 
bones  are  real,  unless  we  can  discover  the  Animal 
Type  to  which  the  bones  belong ;  and  that  there  is 
very  little  in  osteology  which  may  not  be  lost  without 
affecting  an  animal's  grade  of  organisation. 


VARIATION    IN   SKIN   COVERING   OF   MAMMALS 

Even  the  covering  of  the  body  varies  in  the  same 
class,  or  even  order  of  animals,  so  that  the  familiar 
growth  on  the  skin  is  never  its  only  possible  cover- 
ing. The  Indian  ant-eater,  named  Manis,  which 
looks  like  a  gigantic  fir-cone,  the  Armadillo,  which 
sheathes  the  body  in  rings  of  bone,  bearing  only  a 
scanty  development  of  hair,  are  examples  of  mam- 
malian hair,  as  singular  as  the  quills  of  a  Porcupine, 
the  horn  of  a  Rhinoceros,  or  the  growth  of  hair  of 
varying  length  and  stoutness  on  different  parts  of  the 
body  in  various  animals,  or  the  imperfect  develop- 
ment of  hair  in  the  marine  Cetacea.  Among  living 
animals  it  is  enough  for  practical  purposes  to  say 
that  a  mammal  is  clothed  with  hair,  but  in  a  fossil 


ANIMALS  KNOWN  BY  THEIR  BONES    41 

state  the  hair  must  usually  be  lost  beyond  recognition 
from  its  fineness  and  shortness  of  growth. 

VARIATION  IN  SKIN  COVERING  OF  BIRDS 
No  Class  of  living  animals  is  more  homogeneous 
than  Birds ;  and  well-preserved  remains  prove  that, 
at  least  as  far  back  in  time  as  the  Upper  Oolites,  birds 
were  clothed  with  feathers  of  essentially  the  same 
mode  of  growth  and  appearance  as  the  feathers  of 
living  birds.  There  may,  therefore,  be  no  ground  for 
assuming  that  the  covering  was  ever  different,  though 
some  regions  of  the  skin  are  free  from  feathers.  Yet 
the  variations  from  fine  under-down  to  the  scale-like 
feathers  on  the  wings  of  a  Penguin,  or  the  great 
feathers  in  the  wings  of  birds  of  flight,  or  the  double 
quill  of  the  Ostrich  group,  are  calculated  to  yield 
dissimilar  impressions  in  a  fossil  state,  even  if  the 
fine  down  would  be  preserved  in  any  stratum. 

VARIATION  IN  THE  BONES  OF  BIRDS 
Osteologically  there  is  less  variety  in  the  skeleton 
of  birds  than  in  other  great  groups  of  animals.  The 
existing  representatives  do  not  exhaust  its  capability 
for  modification.  The  few  specimens  of  birds  hitherto 
found  in  the  Secondary  strata  have  rudely  removed 
many  differences  in  the  bones  which  separated  living 
birds  from  reptiles ;  so  that  if  only  the  older  fossil 
birds  were  known,  and  the  Tertiary  and  living  birds 
had  not  existed,  a  bird  might  have  been  defined  as 
an  animal  having  its  jaw  armed  with  teeth,  instead  of 
devoid  of  teeth  ;  with  vertebrae  cupped  at  both  ends, 
instead  of  with  a  saddle-shaped  articulation  which  in 
front  is  concave  from  side  from  side,  and  convex  from 
above  downwards ;  in  which  the  bones  of  the  hand 


42  DRAGONS   OF   THE   AIR 

are  separate,  so  that  three  digits  terminating  in  claws 
can  be  applied  to  the  ground,  instead  of  the  meta- 
carpal  bones  being  united  in  a  solid  mass  with  claw- 
less  digits ;  and  in  which  the  tail  is  elongated  like 
the  tail  of  a  lizard.  Yet  the  limits  to  variation  are 
not  to  be  formulated  till  Nature  has  exhausted  all 
her  resources  in  efforts  to  preserve  organic  types  by 
adapting  them  to  changed  circumstances.  Birds  may 
be  regarded  theoretically  as  equally  capable  with 
mammals  of  parting  with  almost  every  distinctive 
structure  in  the  skeleton  by  which  it  is  best  known. 
Even  the  living  frigate  bird  blends  the  early  joints  of 
the  backbone  into  a  compact  mass  like  a  sacrum. 
The  Penguin  has  a  cup-and-ball  articulation  in  the 
early  dorsal  vertebrae,  with  the  ball  in  front.  And  the 
genus  Cypselus  has  the  upper  arm  bone  almost  as 
broad  as  long,  unlike  the  bird  type.  Such  examples 
prove  that  we  are  apt  to  accept  the  predominant 
structures  in  an  animal  type  as  though  they  were 
universal,  and  forget  that  inferences  based,  like  those 
of  early  investigators,  on  limited  materials  may  be 
re-examined  with  advantage. 

VARIATION  IN  THE  BONES  OF  REPTILES 
The  true  Reptilia,  notwithstanding  some  strong  re- 
semblances to  Birds  in  technical  characters  of  the 
skeleton,  display  among  their  surviving  representa- 
tives an  astonishing  diversity  in  the  bony  framework 
of  the  body,  exceeding  that  of  the  mammalia.  This 
unlooked-for  capacity  for  varying  the  plan  of  con- 
struction of  the  skeleton  is  in  harmony  with  the 
diversity  of  structure  in  groups  of  extinct  animals 
to  which  the  name  reptiles  has  also  been  given.  The 
interval  in  form  is  so  vast  between  Serpent  and 


ANIMALS  KNOWN  BY  THEIR  BONES    43 

Tortoise,  and  so  considerable  in  structure  of  the 
skeleton  between  these  and  the  several  groups  of 
Lizards,  Crocodiles,  and  Hatteria,  that  any  other 
diversity  could  not  be  more  surprising.  And  the 
inference  is  reasonable  that  just  as  mammals  live 
in  the  air,  in  the  sea,  on  the  earth,  and  burrow  under 
the  earth,  similar  modes  of  existence  might  be 
expected  for  birds  and  reptiles,  though  no  bird  is 
yet  known  to  have  put  on  the  aspect  of  a  fish,  and 
no  reptiles  have  been  discovered  which  roamed  in 
herds  like  antelopes,  or  lived  in  the  air  like  birds 
or  bats,  unless  these  fossil  flying  animals  prove  on 
examination  to  justify  the  name  by  which  they  are 
known. 

Comparative  study  of  structure  in  this  way  de- 
molishes the  prejudice,  born  of  experience  of  the 
life  which  now  remains  on  earth,  that  the  ideas 
of  Reptile  and  of  Flight  are  incongruous,  and  not 
to  be  combined  in  one  animal.  The  comparative 
study  of  the  parts  of  animals  does  not  leave  the 
student  in  a  chaos  of  possibilities,  but  teaches  us 
that  organic  structures,  which  mark  the  grades  of 
life,  have  only  a  limited  scope  of  change ;  while 
Nature  flings  away  every  part  of  the  skeleton  which 
is  not  vital,  or  changes  its  form  with  altering  circum- 
stances of  existence,  enforced  by  revolutions  of  the 
Earth's  surface  in  geological  time,  in  her  efforts  to 
save  organisms  from  extinction  and  pass  the  grade 
of  life  onward  to  a  later  age. 

The  bones  are  only  of  value  to  the  naturalist  as 
symbols,  inherited  or  acquired,  and  vary  in  value  as 
evidence  of  the  nature  and  association  of  those  vital 
organs  which  differentiate  the  great  groups  of  the 
vertebrata. 


44  DRAGONS   OF   THE   AIR 

These  distinctive  structures,  which  separate  Mam- 
mals, Birds,  and  Reptiles,  are  sometimes  demonstrated 
by  the  impress  of  their  existence  left  on  the  bones  ; 
or  sometimes  they  may  be  inferred  from  the  characters 
of  the  skeleton  as  a  whole. 


CHAPTER  VII 

INTERPRETATION    OF    PTERO- 
DACTYLES  BY  THEIR  SOFT  PARTS 

THE    ORGANS   WHICH   FIX  AN   ANIMAL'S   PLACE 
IN    NATURE 

WE  shall  endeavour  to  ascertain  what  marks 
of  its  grade  of  organisation  the  Pterodactyle 
has  to  show.  The  organs  which  are  capable  of  modi- 
fying the  bones  are  probably  limited  to  the  kidneys, 
the  brain,  and  the  organs  of  respiration.  It  may  be 
sufficient  to  examine  the  latter  two. 

PNEUMATIC  FORAMINA  IN  PTERODACTYLES 
Hermann  von  Meyer,  the  historian  of  the  Ornitho- 
saurs  of  the  Lithographic  Slate,  as  early  as  1837 
described  some  Pterodactyle  bones  from  the  Lias 
of  Franconia,  which  showed  that  air  was  admitted 
into  the  interior  of  the  bones  by  apertures  near  their 
extremities,  which,  from  this  circumstance,  are  known 
as  pneumatic  foramina.  He  drew  the  inference, 
naturally  enough,  that  such  a  structure  is  absolute 
proof  that  the  Pterodactyle  was  a  flying  animal. 
It  was  not  quite  the  right  form  in  which  the  con- 
clusion should  have  been  stated,  because  the  Ostrich 
and  other  birds  which  do  not  fly  have  the  principal 
45 


46  DRAGONS   OF   THE   AIR 

bones  pneumatic.  Afterwards,  in  1859,  the  larger 
bones  which  Professor  Sedgwick,  of  Cambridge, 

fT*1"- \    transmitted   to  Sir   Richard    Owen 

I    \^_^-^—- *A   established  this  condition  as  char- 

\  I    acteristic  of  the  Flying  Reptiles  of 

\r\  \  the  Cambridge  Greensand.     It  was 

\  /  thus  found  as  a  distinctive  structure 

\  (    of  the  bones  both  at  the  beginning 

\  I      and    the    close    of  the    geological 

I        history    of    these    animals.       Von 

y      \  /          Meyer  remarks  that  the  supposition 

\.      j  readily  follows  that  in  the  respiratory 

FIG.  15.    HEAD  OF  Process   there  was  some   similarity 

THE  HUMERUS  OF    between    Pterodactyles    and    Birds. 

tSuorao^S5*  This  cautious  statement   may  per- 

showing  position  of  the  haps    be   due   to   the   circumstance 

pnuTnTrasiCdI°of Th" ton?6  that   in    many  animals  air  cavities 

as  in  a  bird  ^     developecl      jn     the     ^u\\     wjth. 

out  being  connected  with  organs  of  respiration.  It 
is  well  known  that  the  bulk  of  the  Elephant's  head 
is  due  to  the  brain  cavity  being  protected  with  an 
envelope  formed  of  large  air  cells.  Small  air  cells 
are  seen  in  the  skulls  of  oxen,  pigs,  and  many  other 
mammals,  as  well  as  in  the  human  forehead.  The 
head  of  a  bird  like  the  Owl  owes  something  of  its 
imposing  appearance  to  the  way  in  which  its  mass 
is  enlarged  by  the  dense  covering  of  air  cells  in  the 
bones  above  the  brain,  like  that  seen  in  some  Creta- 
ceous Pterodactyles.  Nor  are  the  skulls  of  Crocodiles 
or  Tortoises  exceptions  to  the  general  rule  that  an 
animal's  head  bones  may  be  pneumatic  without 
implying  a  pneumatic  prolongation  of  air  from  the 
lungs.  The  mere  presence  of  air  cells  without  speci- 
fication of  the  region  of  the  skeleton  in  which  they 


PTERODACTYLES  47 

occur  is  not  remarkable.  The  holes  by  which  air 
enters  the  bones  are  usually  much  larger  in  Pterodac- 
tyles  than  in  Birds,  but  the  entrance  to  the  air  cell 
prolonged  into  the  bones  is  the  same  in  form  and 
position  in  both  groups.  So  far  as  can  be  judged 
by  this  character,  there  is  no  difference  between  them. 
The  importance  of  the  comparison  can  only  be  ap- 
preciated by  examining  the  bones  side  by  side.  In 
the  upper  arm  bone  of  a  bird,  on  what  is  known 
as  the  ulnar  border,  near  to  the  shoulder  joint,  and 
on  the  side  nearest  to  it,  is  the  entrance  to  the  air 
cell  in  the  humerus.  In  the  Pterodactyle  the  corre- 
sponding foramen  has  the  same  position,  form,  and 
size,  and  is  not  one  large  hole,  but  a  reticulation 
of  small  perforations,  one  beyond  another,  exactly 
such  as  are  seen  in  the  entrance  to  the  air  cell  in  the 
bone  of  a  bird,  in  which  the  pneumatic  character 
is  found.  For  it  is  not  every  bird  of  flight  which  has 
this  pneumatic  condition  of  the  bones  ;  and  Dr.  Crisp 
stated  that  quite  a  number  of  birds— the  Swallow, 
Martin,  Snipe,  Canary,  Wood-wren  and  Willow-wren, 
Whinchat,  Glossy-starling,  Spotted-fly-catcher,  and 
Black-headed  Bunting — have  no  air  in  their  bones. 
And  it  is  well  known  that  in  many  birds,  especially 
water  birds,  it  is  only  the  upper  bones  of  the  limbs 
which  are  pneumatic,  while  the  smaller  bones  retain 
the  marrow. 

LUNGS  AND  AIR  CELLS 

It  may  be  well  to  remember  that  the  lungs  of  a 
bird  are  differently  conditioned  from  those  of  any 
other  animal.  Instead  of  hanging  freely  suspended 
in  the  cone-shaped  chamber  of  the  thorax  formed  by 
the  ribs  and  sternum,  they  are  firmly  fixed  oa  each 


48 


DRAGONS   OF   THE   AIR 


side,  so  that  the  ribs  deeply  indent  them  and  hold 
them  in  place.  The  lungs  have  the  usual  internal 
structure,  being  made  up  of  branching  cells.  The 
chief  peculiarity  consists  in  the  way  in  which  the  air 
passes  not  only  into  them,  but  through  them.  The 
air  tube  of  the  throat  of  a  bird,  unlike  that  of  a 
man,  has  the  organ  of  voice,  not  at  the  upper  end 
in  the  form  of  a  larynx,  but  at  the  lower  end,  form- 
ing what  is  termed  a  syrinx.  There  is  no  evidence 
of  this  in  a  fossil  state,  although  in  a  few  birds  the 


FIG.   16.     LUNGS  OF  THE   BIRD  APTERYX 

PARTLY  OPENED  ON   THE   RIGHT-HAND  SIDE 

The  circles  are  openings  of  the  bronchial  tubes  on  the  surface  of  the  lung 

The  notches  on  the  inner  edges  of  the  lungs  are  impressions  of  the  ribs 

(After  R.  Owen) 

rings  of  the  trachaea  become  ossified,  and  are  pre- 
served. But  below  the  syrinx  the  trachaea  divides 
into  two  bronchi,  tubes  which  carry  the  ringed 
character  into  the  lungs  for  some  distance,  and 
these  give  off  branches  termed  bronchial  tubes,  the 
finer  subdivisions  from  which,  in  their  clustered 
minute  branching  sacs,  make  up  the  substance  of 
the  lung.  There  is  nothing  exceptional  in  that.  But 
towards  the  outer  or  middle  part  of  the  ventral  or 


PTERODACTYLES  49 

under  surface  of  the  lungs,  four  or  five  rounded 
openings  are  seen  on  each  side.  Each  of  these 
openings  resembles  the  entrance  of  the  air  cell  into 
a  bone,  since  it  displays  several  smaller  openings 
which  lead  to  it.  Each  opening  from  the  lung 
leads  to  an  air  cell.  Those  cells  may  be  regarded  as 
the  blowing  out  of  the  membrane  which  covers  the 
lungs  into  a  film  which  holds  air  like  a  mass  of  soap 
bubbles,  until  the  whole  cavity  of  the  body  of  a 


FIG.   17.      THE   BODY  OF  AN   OSTRICH   LAID  OPEN 

TO  SHOW  THE  AIR  CELLS  WHICH   EXTEND 

THROUGH   ITS   LENGTH 

(After  Georges  Roche) 

bird  from  neck  to  tail  is  occupied  by  sacculated  air 
cells,  commonly  ten  in  number,  five  on  each  side, 
though  two  frequently  blend  at  the  base  of  the  neck 
in  the  region  of  the  V-shaped  bone  named  the 
clavicle  or  furculum,  popularly  known  as  the  merry- 
thought. Most  people  have  seen  some  at  least  of 


50  DRAGONS   OF   THE   AIR 

these  semi-transparent  bladder-like  air  cells  beneath 
the  skin  in  the  abdominal  region  of  a  fowl.  The  cells 
have  names  from  their  positions,  and  on  each  side 
one  is  abdominal,  two  are  thoracic,  one  clavicular, 
and  one  cervical,  which  last  is  at  the  base  of  the 
neck.  The  clavicular  and  abdominal  air  cells  are 
perhaps  the  most  interesting.  The  air  cell  termed 
clavicular  sends  a  process  outward  towards  the  arm, 
along  with  the  blood  vessels  which  supply  the  arm. 
Thus  this  air  cell,  entering  the  region  of  the  axilla 
or  arm-pit,  enters  the  upper  arm  bone  usually  on  its 
under  side,  close  to  the  articular  head  of  the  humerus, 
and  in  the  same  way  the  air  may  pass  from  bone  to 
bone  through  every  bone  in  the  fore  limb.  The  hind 
limbs  similarly  receive  air  from  the  abdominal  air 
cell,  which  supplies  the  femur  and  other  bones  of 
the  leg,  the  sacrum,  and  the  tail.  But  the  joints  of 
the  backbone  in  front  of  the  sacrum  receive  their  air 
from  the  cervical  air  sac.  The  air  cells  are  not 
limited  to  the  bones,  but  ramify  through  the  body, 
and  in  some  cases  extend  among  the  muscles.  A 
bird  may  be  said  to  breathe  not  only  with  its  lungs, 
but  with  its  whole  body.  And  it  is  even  affirmed 
that  respiration  has  been  carried  on  through  a  broken 
arm  bone  when  the  throat  was  closed,  and  the  bird 
under  water. 

Birds  differ  greatly  in  the  extent  to  which  the  air- 
cell  system  prolonged  from  the  lungs  is  developed, 
some  having  the  air  absent  from  every  bone,  while 
others,  like  the  Swift,  are  reputed  to  have  air  in  every 
bone  of  the  body. 

Comparison  shows  that  in  so  far  as  the  bones  are 
the  same  in  Bird  and  Ornithosaur,  the  evidence  of 
the  air  cells  entering  them  extends  to  resemblance, 


PTERODACTYLES  51 

if  not  coincidence,  in  every  detail.  No  living  group 
of  animals  except  birds  has  pneumatic  limb  bones, 
in  relation  to  the  lungs ;  so  that  it  is  reasonable  to 
conclude  that  the  identical  structures  in  the  bones 
were  due  to  the  same  cause  in  both  the  living  and 
extinct  groups  of  animals.  It  is  impossible  to  say 
that  the  lungs  were  identical  in  Birds  and  Ptero- 
clactyles,  but  so  far  as  evidence  goes,  there  is  no 
ground  for  supposing  them  to  have  been  different. 

THE   LUNGS   OF   REPTILES 

There  is  nothing  comparable  to  birds,  either  in  the 
lungs  of  living  reptiles  or  in  their  relation  to  the 


FIG.  l8.      THE  SIDE   OF  THE   BODY  OF  A   CHAMELEON 
Ribs  removed  to  show  the  sacculate  branched  form  of  the  lung  - 

bones.  The  Chameleon  is  remarkable  in  that  the 
lung  is  not  a  simple  bladder  prolonged  through 
the  whole  length  of  the  body  cavity,  as  in  a  serpent, 
but  it  develops  a  number  of  large  lateral  branches 
visible  when  the  body  is  laid  open.  Except  near 
the  trachaea,  where  the  tissue  has  the  usual  density 
of  a  lizard  lung,  the  air  cell  is  scarcely  more  com- 
plicated than  the  air  bladder  of  a  fish,  and  does  not 
enter  into  any  bone  of  the  skeleton.  And  although 


52  DRAGONS   OF  THE   AIR 

many  fishes  like  the  Loach  have  the  swim  bladder 
surrounded  by  bone  connected  with  the  head,  it  offers 
no  analogy  to  the  pneumatic  condition  of  the  bones 
in  the  Pterodactyle. 

THE  FORM   OF  THE   BRAIN   CAVITY 

But  the  identity  of  the  pneumatic  foramina  in 
Birds  and  Flying  Reptiles  is  not  a  character  which 
stands  by  itself  as  evidence  of  organisation,  for  a 
mould  of  the  form  of  the  brain  case  contributes 
evidence  of  another  structural  condition  which  throws 
some  light  on  the  nature  of  Ornithosaurs.  Among 
many  of  the  lower  animals,  such  as  turtles,  the  brain 
does  not  fill  the  chamber  in  the  dry  skull,  in  which 
the  same  bones  are  found  as  are  moulded  upon  the 
brain  in  higher  animals.  For  the  brain  case  in  such 
reptiles  is  commonly  an  envelope  of  cartilage,  as 
among  certain  fishes ;  and  except  among  serpents, 
the  Ophidia,  the  bones  do  not  completely  close  the 
reptilian  brain  case  in  front.  The  brain  fills  the  brain 
case  completely  among  birds.  A  mould  from  its 
interior  is  almost  as  definite  in  displaying  the  several 
parts  of  which  it  is  formed  as  the  actual  brain  would 
be.  And  the  chief  regions  of  the  brain  in  a  bird — 
cerebrum,  optic  lobes,  cerebellum — show  singularly 
little  variation  in  proportion  or  position.  The  essen- 
tial fact  in  a  bird's  brain,  which  separates  it  absolutely 
from  all  other  animals,  is  that  the  pair  of  nerve 
masses  known  as  the  optic  lobes  are  thrust  out  at 
the  sides,  so  that  the  large  cerebral  hemispheres 
extend  partly  over  them  as  they  extend  between 
them  to  abut  against  the  cerebellum.  This  remark- 
able condition  has  no  parallel  among  other  verte- 
brate animals.  In  Fishes,  Amphibians,  Reptiles,  and 


PTERODACTYLES 


53 


Mammals  the  linear  succession  of  the  several  parts 
of  the  brain  is  never  departed  from  ;  and  any  appear- 
ance of  variation  from  it  among  mammals  is  more 
apparent  than  real,  for  the  linear  succession  may  be 
seen  in  the  young  calf  till  the  cerebral  hemispheres 
grow  upward  and  lop  backward,  so  as  to  hide  the 


Alligator 


Lias  Ornithorhynchus          Owl 

Pterodactyle 

FIG.   19'.      THE   FORM   OF  THE   BRAIN 

relatively  small  brain  masses  which  correspond  to 
the  optic  lobes  of  reptiles,  extending  over  these 
corpora-quadrigemina,  as  they  are  named,  so  as  to 
cover  more  or  less  of  the  mass  of  the  cerebellum. 
From  these  conditions  of  the  brain  and  skull,  it 
would  not  be  possible  to  mistake  a  mould  from 


54  DRAGONS   OF  THE   AIR 

the  brain  case  of  a  bird  for  that  of  a  reptile,  though 
in  some  conditions  of  preservation  it  is  conceivable 
that  the  mould  of  the  brain  of  a  bird  might  be  dis- 
tinguished with  difficulty  from  that  of  the  brain  in  the 
lowest  mammals.  Taken  by  itself,  the  avian  form  of 
brain  in  an  animal  would  be  as  good  evidence  that 
its  grade  of  organisation  was  that  of  a  bird  as  could 
be  offered. 

THE   BRAIN   IN   SOLENHOFEN   PTERODACTYLES 

It  happens  that  moulds  of  the  brain  of  Ptero- 
dactyles,  more  or  less  complete,  are  met  with  of 
all  geological  ages— Liassic,  Oolitic,  and  Cretaceous. 
The  Solenhofen  Slate  is  the  only  deposit  in  Europe 
in  which  Pterodactyle  skulls  can  be  said  to  be  fairly 
numerous.  They  commonly  have  the  bones  so  thin 
as  to  show  the  form  of  the  upper  surface  of  the 
mould  of  the  brain,  or  the  bones  have  scaled  off 
the  mould,  or  remain  in  the  counterpart  slab  of  stone, 
so  as  to  lay  bare  the  shape  of  the  brain  mass. 

In  the  Museum  at  Heidelberg  a  skull  of  this  kind 
is  seen  in  the  long-tailed  genus  of  Pterodactyles 
named  Rhamphorhynchus.  It  shows  the  large 
rounded  cerebral  hemispheres,  which  extend  in 
front  of  cerebral  masses  of  smaller  size  a  little 
below  them  in  position,  which  perhaps  are  as  like 
the  brain  of  a  monotreme  mammal  as  a  bird. 

The  short-tailed  Pterodactylus  described  by  Cuvier 
has  the  cerebral  hemispheres  very  similar  to  those 
of  a  bird,  but  the  relations  of  the  hinder  parts  of 
the  brain  to  each  other  are  less  clear. 

The  first  specimen  to  show  the  back  of  the  brain 
was  found  by  Mr.  John  Francis  Walker,  M.A.,  in  the 
Cambridge  Greensand.  I  was  able  to  remove  the 


PTERODACTYLES  55 

thick  covering  of  cellular  bone  which  originally 
extended  above  it,  and  thus  expose  evidence  that 
in  the  mutual  relations  of  the  fore  and  hind  parts 
of  the  brain  bird  and  ornithosaur  were  practically 
identical.  Another  Cambridge  Greensand  skull 
showed  that  in  the  genus  Ornithocheirus  the  optic 
lobes  of  the  brain  are  developed  laterally,  as  in  birds. 
That  skull  was  isolated  and  imperfect.  But  about  the 
same  time  the  late  Rev.  W.  Fox,  of  Brixton,  in  the 
Isle  of  Wight,  obtained  from  Wealden  beds  another 
skull,  with  jaws,  teeth,  and  the  principal  bones  of 
the  skeleton,  which  showed  that  the  Wealden  Ptero- 
dactyle  Ornithodesmus  had  a  similar  and  bird -like 
brain.  In  1888  Mr.  E.  T.  Newton,  F.R.S.,  obtained  a 
skull  from  the  Upper  Lias,  uncrushed  and  free  from 
distortion.  This  made  known  the  natural  mould  of 
the  brain,  which  shows  the  cerebral  hemispheres,  optic 
lobes,  and  cerebellum  more  distinctly  than  in  the  speci- 
mens previously  known.  In  some  respects  it  recalls 
the  Heidelberg  brain  of  Rhamphorhynchus  in  the 
apparently  transverse  subdivision  of  the  optic  lobes, 
but  it  is  unmistakably  bird-like,  and  quite  unlike  any 
reptile. 

IMPORTANCE  OF  THE  BRAIN  AND  BREATHING 
ORGANS 

So  far  as  the  evidence  goes,  it  appears  that  these 
fossil  flying  animals  show  no  substantial  differences 
from  birds,  either  in  the  mould  of  the  brain  or  the 
impress  of  the  breathing  organs  upon  the  bones. 
These  approximations  to  birds  of  the  nervous  and 
respiratory  systems,  which  are  beyond  question  two 
of  the  most  important  of  the  vital  organs  of  an 
animal,  and  distinctive  beyond  all  others  of  birds, 


56  DRAGONS   OF   THE   AIR 

place  the  naturalist  in  a  singular  dilemma.  He  must 
elect  whether  he  will  trust  his  interpretation  to  the 
soft  organs,  which  among  existing  animals  never  vary 
their  type  in  the  great  classes  of  vertebrate  animals, 
and  on  which  the  animal  is  defined  as  something 
distinct  from  its  envelope  the  skeleton  and  its  ap- 
pendages the  limbs,  or  whether  he  will  ignore  them. 
The  answer  must  choose  substantially  between  belief 
that  the  existing  order  of  Nature  gives  warrant  for 
believing  that  these  vital  characteristics  which  have 
been  discussed  might  equally  coexist  with  the  skele- 
ton of  a  mammal  or  a  reptile,  as  with  that  of  a  bird, 
for  which  there  is  no  particle  of  evidence  in  existing 
life.  Or,  as  an  alternative,  the  fact  must  be  accepted 
that  birds  only  have  such  vital  organs  as  are  here 
found,  and  therefore  the  skeleton,  that  may  be  asso- 
ciated with  them,  cannot  affect  the  reference  of  the 
type  to  the  same  division  of  the  animal  kingdom  as 
birds.  The  decision  need  not  be  made  without  further 
consideration.  But  brain  and  breathing  organs  of  the 
avian  type  are  structures  of  a  different  order  of 
stability  in  most  animals  from  the  bones,  which  vary 
to  a  remarkable  extent  in  almost  every  ordinal  group 
of  animals. 

TEMPERATURE  OF  THE  BLOOD 
The  organs  of  circulation  and  digestion  are  neces- 
sarily unknown.  There  are  reasons  why  the  blood 
may  have  been  hot,  such  as  the  evidences  from  the 
wings  of  exceptional  activity ;  though  the  tempera- 
ture depends  more  upon  the  amount  of  blood  in  the 
body  than  upon  the  apparatus  by  which  it  is  dis- 
tributed. We  speak  of  a  Crocodile  as  cold-blooded, 
yet  it  is  an  animal  with  a  four-chambered  heart  not 


PTERODACTYLES  57 

incomparable  with  that  of  a  bird.  On  the  other  hand, 
the  Tunny,  a  sort  of  giant  Mackerel,  is  a  fish  with  a 
three-chambered  heart,  only  breathing  the  air  dis- 
solved in  water,  which  has  blood  as  warm  as  a 
mammal,  its  temperature  being  compared  to  that  of 
a  pig.  Several  fishes  have  blood  as  warm  as  that  of 
Manis,  the  scaly  ant-eater  ;  and  many  birds  have 
hotter  blood  than  mammals.  The  term  "hot-blooded," 
as  distinct  from  "  cold-blooded,"  applied  to  animals,  is 
relative  to  the  arbitrary  human  standard  of  experi- 
ence, and  expresses  no  more  than  the  circumstance 
that  mammals  and  birds  are  warmer  animals  than 
reptiles  and  fishes. 

The  exceptional  temperature  of  the  Flying  Fish 
has  led  to  a  vague  impression  that  physical  activity 
and  its  effect  upon  the  amount  of  blood  which  vigour 
of  movement  circulates,  are  more  important  in  raising 
an  animal's  temperature  than  possession  of  the  circu- 
latory organs  commonly  associated  with  hot  blood, 
which  drive  the  blood  in  distinct  courses  through  the 
body  and  breathing  organs.  Yet  the  kind  of  heart 
which  is  always  associated  with  vital  structures  such 
as  Pterodactyles  are  inferred  to  have  possessed  from 
the  brain  mould  and  the  pneumatic  foramina  in  the 
bones,  is  the  four-chambered  heart  of  the  bird  and 
the  mammal.  Considering  these  organs  alone — of 
which  the  fossil  bones  yield  evidence — we  might 
anticipate,  by  the  law  of  known  association  of  struc- 
tures, that  nothing  distinctly  reptilian  existed  in  the 
other  soft  part  of  the  vital  organisation,  because  there 
is  no  evidence  in  favour  of  or  against  such  a  possi- 
bility. 


CHAPTER  VIII 
THE    PLAN    OF   THE    SKELETON 

WHILE  these  animals  are  incontestably  nearer 
to  birds  than  to  any  other  animals  in  their 
plan  of  organisation,  thus  far  no  proof  has  been 
found  that  they  are  birds,  or  can  be  included  in 
the  same  division  of  vertebrate  life  with  feathered 
animals.  It  is  one  of  the  oldest  and  soundest  teach- 
ings of  Linnaeus  that  a  bird  is  known  by  its  feathers ; 
and  the  record  is  a  blank  as  to  any  covering  to  the 
skin  in  Pterodactyles.  There  is  the  strongest  prob- 
ability against  feathers  having  existed  such  as  are 
known  in  the  Archseopteryx,  because  every  Solen- 
hofen  Ornithosaur  appears  to  have  the  body  devoid 
of  visible  or  preservable  covering,  while  the  two  birds 
known  from  the  Solenhofen  Slate  deposit  are  well 
clothed  with  feathers  in  perfect  preservation.  We 
turn  from  the  skin  to  the  skeleton. 

The  plan  on  which  the  skeleton  is  constructed 
remains  as  evidence  of  the  animal's  place  in  nature, 
which  is  capable  of  affording  demonstration  on  which 
absolute  reliance  would  have  been  placed,  if  the  brain 
and  pneumatic  foramina  had  remained  undiscovered. 
With  the  entire  skeleton  before  us,  it  is  inconceivable 
that  anatomical  science  should  fail  to  discover  the 
58 


THE   PLAN   OF   THE  SKELETON       59 

true  nature  of  the  animal  to  which  it  belonged,  by 
the  method  of  comparing  one  animal  with  another. 
There  is  no  lack  of  this  kind  of  evidence  of  Ptero- 
dactyles  in  the  three  or  four  scores  of  skeletons,  and 
thousands  of  isolated  or  associated  bones,  preserved 
in  the  public  museums  of  Europe  and  America. 

I  may  recall  the  circumstance  that  the  discovery  of 
skeletons  of  fossil  animals  has  occasionally  followed 
upon  the  interpretation  of  a  single  fragment,  from 
which  the  animal  has  been  well  defined,  and  some- 
times accurately  drawn,  before  it  was  ever  seen.  So 
I  propose,  before  drawing  any  conclusions  from  the 
skeletons  in  the  entirety  of  their  construction,  to 
examine  them  bone  by  bone,  and  region  by  region, 
for  evidence  that  will  manifest  the  nature  of  this 
brood  of  Dragons.  Their  living  kindred,  and  perhaps 
their  extinct  allies,  assembled  as  a  jury,  may  be  able 
to  determine  whether  resemblances  exist  between 
them,  and  whether  such  similarity  between  the  bones 
as  exists  is  a  common  inheritance,  or  is  a  common 
acquisition  due  to  similar  ways  of  life,  and  no  evi- 
dence of  the  grade  of  the  organism  among  vertebrate 
animals. 

The  bones  of  these  Ornithosaurs,  when  found 
isolated,  first  have  to  be  separated  from  the  organisms 
with  which  they  are  associated  and  mixed  in  the 
geological  strata.  This  discrimination  is  accomplished 
in  the  first  instance  by  means  of  the  texture  of  the 
surface.  The  density  and  polish  of  the  bones  is 
even  more  marked  than  in  the  bones  of  birds,  and  is 
usually  associated  with  a  peculiar  thinness  of  sub- 
stance of  the  bone,  which  is  comparable  to  the  con- 
dition in  a  bird,  though  usually  a  little  stouter,  so 
that  the  bones  resist  crushing  better.  Pterodactyle 


60  DRAGONS   OF  THE   AIR 

bones  in  many  instances  are  recognised  by  their 
straightness  and  comparatively  uniform  dimensions, 
due  to  the  exceptional  number  of  long  bones  which 
enter  into  the  structure  of  the  wing  as  compared 
with  birds.  When  the  bones  are  unerringly  deter- 
mined as  Ornithosaurian,  they  are  placed  side  by 
side  with  all  the  bones  which  are  most  like  them,  till, 
judged  by  the  standard  of  the  structures  of  living 
animals,  the  fossil  is  found  to  show  a  composite  con- 
struction as  though  it  were  not  one  animal  but  many, 
while  its  individual  bones  often  show  equally  compo- 
site characters,  as  though  parts  of  the  corresponding 
bone  in  several  animals  had  been  cunningly  fitted 
together  and  moulded  into  shape. 

THE  PLAN  OF  THE  HEAD  IN  ORNITHOSAURS 
The  head  is  always  the  most  instructive  part  of  an 
animal.  It  is  less  than  an  inch  long  in  the  small 
Solenhofen  skeleton  named  Pterodactylus  brevirostris, 
and  is  said  to  be  three  feet  nine  inches  long  in  the 
toothless  Pterodactyle  Ornithostoma  from  the  Chalk 
of  Kansas.  Most  of  these  animals  have  a  long, 
slender,  conical  form  of  head,  tapering  to  the  point 
like  the  beak  of  a  Heron,  forming  a  long  triangle 
when  seen  from  above  or  from  the  side.  Sometimes 
the  head  is  depressed  in  front,  with  the  beak  flattened 
or  rounded  as  in  a  Duck  or  Goose,  and  occasionally  in 
some  Wealden  and  Greensand  species  the  jaws  are 
truncated  in  front  in  a  massive  snout  quite  unlike 
any  bird.  The  back  of  the  head  is  sometimes 
rounded  as  among  birds,  showing  a  smooth  pear- 
shaped  posterior  convexity  in  the  region  of  the  brain. 
Sometimes  the  back  of  the  head  is  square  and  verti- 
cal or  oblique.  Occasionally  a  great  crest  of  cellular 


THE   PLAN   OF   THE   SKELETON      61 

tissue  is  extended  backward  from  above  the  brain 
case  over  the  spines  of  the  neck  bones. 

There  are  always  from  two  to  four  lateral  openings 
in  the  skull.  First,  the  nostril  is  nearest  to  the  ex- 
tremity of  the  beak.  Secondly,  the  orbits  of  the 
eyes  are  placed  far  backward.  These  two  openings 
are  always  present.  The  nostril  may  incline  upward. 
The  orbits  of  the  eyes  are  usually  lateral,  though 
their  upper  borders  sometimes  closely  approximate, 
as  in  the  woodpecker-like  types  from  the  Solen- 
hofen  Slate  named  Pterodactylus  Kochi,  now  separated 
as  another  genus.  In  most  genera  there  is  an  opening 
in  the  side  of  the  head,  between  the  eye  hole  and  the 
nostril,  known  as  the  antorbital  vacuity ;  and  another 
opening,  which  is  variable  in  size  and  known  as  the 
temporal  vacuity,  is  placed  behind  the  eye.  The 
former  is  common  in  the  skulls  of  birds,  the  latter  is 
absent  from  all  birds  and  found  in  many  reptiles. 

The  palate  is  usually  imperfectly  seen,  but  English 
and  American  specimens  have  shown  that  it  has 
much  in  common  with  the  palate  in  birds,  though  it 
varies  greatly  in  form  of  the  bones  in  representatives 
from  the  Lias,  Oolites,  and  Cretaceous  rocks. 

From  the  scientific  aspect  the  relative  size  of  the 
head,  its  form,  and  the  positions  and  dimensions  of 
its  apertures  and  processes,  are  of  little  importance 
in  comparison  with  its  plan  of  construction,  as  evi- 
denced by  the  positions  and  relations  to  each  other 
of  the  bones  of  which  it  is  formed.  There  usually  is 
some  difficulty  in  stating  the  limits  of  the  bones  of 
the  skull,  because  in  Pterodactyles,  as  among  birds, 
they  usually  blend  together,  so  that  in  the  adult 
animal  the  sutures  between  the  bones  are  commonly 
obliterated. 


62  DRAGONS   OF  THE   AIR 

Bones  have  relations  to  each  other  and  places  in 
the  head  which  can  only  change  as  the  organs  with 
which  they  are  associated  change  their  positions.  No 
matter  what  the  position  of  a  nostril  may  be — at  the 
extremity  of  a  long  snout,  as  in  an  ant-eater,  or  far 
back  at  the  top  of  the  head  in  a  porpoise,  or  at  the 
side  of  the  head  in  a  bird — it  is  always  bordered  by 
substantially  the  same  bones,  which  vary  in  length 
and  size  with  the  changing  place  of  the  nostril  and 
the  form  of  the  head.  Every  region  of  the  head  is 
defined  by  this  method  of  construction  ;  so  that  eye 
holes  and  nose  holes,  brain  case  and  jaw  bones, 
palate  and  teeth,  beak,  and  back  of  the  skull  are  all 
instructive  to  those  who  seek  out  the  life-history  of 
these  animals.  We  may  briefly  examine  the  head 
of  an  Ornithosaurian. 

BONES  ABOUT  THE  NOSTRIL 
No  matter  what  its  form  may  be,  the  head  of  an 
Ornithosaur  always  terminates  in  front  in  a  single 
bone  called  the  intermaxillary.  It  sends  a  bar  of 
bone  backward  above  the  visible  nostrils,  between 
them ;  and  a  bar  on  each  side  forms  the  margin  of 
the  jaw  in  which  teeth  are  implanted.  The  bone 
varies  in  depth,  length,  sharpness,  bluntness,  slender- 
ness,  and  massiveness.  As  the  bone  becomes  long 
the  jaw  is  compressed  from  side  to  side,  and  the 
openings  of  the  nostrils  are  removed  backward  to 
an  increasing  distance  from  the  extremity  of  the 
beak. 

The  outer  and  hinder  border  of  the  nostril  is  made 
by  another  bone  named  the  maxillary  bone,  which  is 
usually  much  shorter  than  the  premaxillary.  It 
contains  the  hinderrnost  teeth,  which  rarely  differ 


THE   PLAN   OF  THE   SKELETON      63 

from  those  in  front,  except  in  sometimes  being 
smaller. 

The  nasal  bones,  which  always  make  the  upper 
and  hinder  border  of  the  nostrils,  meet  each  other 
above  them,  in  the  middle  line  of  the  beak. 

The  nostrils  are  unusually  large  in  the  Lias  genus 
named  Dimorphodon,  and  small  in  species  of  the 
genus  Rhamphorhynchus  from  Solenhofen.  Such 


phorhynchus 


Showing  that  the  extremity  of  the  jaws  in  Rhamphorhynchus  was 
sheathed  in  horn  as  in  the  giant  Kingfisher,  since  the  jaws 
similarly  gape  in  front. 

The  hyoid  bones  are  below  the  lower  jaw  in  the  Pterodactyle. 

differences  result  from  the  relative  dimensions  and 
proportions  of  these  three  bones  which  margin  the 
nasal  vacuity,  and  by  varying  growth  of  their  front 
margins  or  of  their  hinder  margins  govern  the  form 
of  the  snout. 

The  jaws  are  most  massive  in  the  genera  known  from 
the  Wealden  beds  to  the  Chalk.   The  palatal  surface  is 


64  DRAGONS   OF   THE   AIR 

commonly  flat  or  convex,  and  often  marked  by  an 
elevated  median  ridge  which  corresponds  to  a  groove 
in  the  lower  jaw,  though  the  median  ridge  sometimes 
divides  the  palate  into  two  parallel  concave  channels. 
The  jaw  is  margined  with  teeth  which  are  rarely 
fewer  than  ten  or  more  than  twenty  on  each  side. 
They  are  sharp,  compressed  from  side  to  side,  curved 
inward,  and  never  have  a  saw-like  edge  on  the  back 
and  front  margins.  No  teeth  occur  upon  the  bones 
of  the  palate. 

In  most  birds  there  is  a  large  vacuity  in  the  side 
of  the  head  between  the  nostril  and  the  orbit  of  the 
eye,  partly  separated  from  it  by  the  bone  which 
carries  the  duct  for  tears  named  the  lachrymal  bone. 
The  same  preorbital  vacuity  is  present  in  all  long- 
tailed  Pterodactyles,  though  it  is  either  less  com- 
pletely defined  or  absent  in  the  group  with  short 
tails.  It  affords  excellent  distinctive  characters  for 
defining  the  genera.  In  the  long- tailed  genus 
Scaphognathus  from  Solenhofen  this  preorbital  open- 
ing is  much  larger  than  the  nostril,  while  in  Dimor- 
phodon  these  vacuities  are  of  about  equal  size. 
Rhamphorhynchus  is  distinguished  by  the  small  size 
of  the  antorbital  vacuity,  which  is  placed  lower  than 
the  nostril  on  the  side  of  the  face.  The  aperture  is 
always  imperfectly  defined  in  Pterodactylus,  and  is 
a  relatively  small  vacuity  compared  with  the  long 
nostril.  In  Ptenodracon  the  antorbital  vacuity 
appears  to  have  no  existence  separate  from  the  nostril 
which  adjoins  the  eye  hole.  And  so  far  as  is  known  at 
present  there  is  no  lateral  opening  in  advance  of  the 
eye  in  the  skull  in  any  Ornithosaur  from  Cretaceous 
rocks,  though  the  toothless  Ornithostoma  is  the  only 
genus  with  the  skull  complete.  When  a  separate 


THE   PLAN   OF   THE   SKELETON      65 

antorbital  vacuity  exists,  it  is  bordered  by  the  maxil- 
lary bone  in  front,  and  by  the  malar  bone  behind. 
The  prefrontal  bone  is  at  its  upper  angle.  That  bone 
is  known  in  a  separate  state  in  reptiles  and,  I  think,  in 
monotreme  mammals.  Its  identity  is  soon  lost  in 
the  mammal,  and  its  function  in  the  skull  is  different 
from  the  corresponding  bone  in  Pterodactyles. 

BONES   ABOUT   THE   EYES 

The  third  opening  in  the  side  of  the  head,  counting 
from  before  backward,  is  the  orbit  of  the  eye.    In  this 


Rhamphorhynchus 


Orbit  of  the  eye 


FIG.  21.      UPPER   SURFACE   OF   SKULL   OF   THE   HERON 
Compared  with  the  same  aspect  of  the  skull  of  Rhamphorhynchus 

vacuity  is  often  seen  the  sclerotic  circle  of  overlapping 
bones  formed  in  the  external  membrane  of  the  eye, 
like  those  in  nocturnal  birds  and  some  reptiles.  The 


66  DRAGONS   OF   THE   AIR 

eye  hole  varies  in  form  from  an  inverted  pear-shape 
to  an  oblique  or  transverse  oval,  or  a  nearly  circular 
outline.  It  is  margined  by  the  frontal  bone  above  ; 
the  tear  bone  or  lachrymal,  and  the  malar  or  cheek 
bone  in  front ;  while  the  bones  behind  appear  to  be 
the  quadrato-jugal  and  post-frontal  bones,  though  the 
bones  about  the  eye  are  somewhat  differently  ar- 
ranged in  different  genera. 

The  eyes  were  frequently,  if  not  always,  in  contact 
with  the  anterior  walls  of  the  brain  case,  as  in  many 
birds,  and  are  always  far  back  in  the  side  of  the  head. 
In  Dimorphodon  they  are  in  front  of  the  articulation 
of  the  lower  jaw ;  in  Rhamphorhynchus,  above  that 
articulation ;  while  in  Ornithostoma  they  are  behind 
the  articulation  for  the  jaw.  This  change  is  governed 
by  the  position  of  the  quadrate  bone,  which  is  vertical 
in  the  Lias  genus,  inclined  obliquely  forward  in  the 
fossils  from  the  Oolites,  and  so  much  inclined  in  the 
Chalk  fossil  that  the  small  orbit  is  thrown  relatively 
further  back. 

Thus  far  the  chief  difference  in  the  Pterodactyle 
skull  from  that  of  a  bird  is  in  the  way  in  which  the 
malar  arch  is  prolonged  backward  on  each  side.  It  is 
a  slender  bar  of  bone  in  birds,  without  contributing 
ascending  processes  to  border  vacuities  in  the  side 
of  the  face,  while  in  these  fossil  animals  the  lateral 
openings  are  partly  separated  by  the  ascending  pro- 
cesses of  these  bones.  This  divergence  from  birds, 
in  the  malar  bone  entering  the  orbit  of  the  eye 
is  approximated  to  among  reptiles  and  mammals, 
though  the  conditions,  and  perhaps  the  presence  of  a 
bone  like  the  post-orbital  bone,  are  paralleled  only 
among  Reptiles.  The  Pterodactyles  differ  among 
themselves  enough  for  the  head  to  make  a  near 


THE    PLAN    OF   THE   SKELETON       67 

approach  to  Reptiles  in  Dimorphodon,  and  to  Birds 
in  Pterodactylus.  In  the  Ground  Hornbill  and  the 
Shoebill  the  lachrymal  bones  in  front  of  the  orbits 
of  the  eyes  grow  down  to  meet  the  malar  bars  with- 
out uniting  with  them.  The  post-frontal  region  also 
is  prolonged  downward  almost  as  far  as  the  malar 
bar,  as  though  to  show  that  a  bird  might  have  its 
orbital  circle  formed  in  the  same  way  and  by  the 
same  bones  as  in  Pterodactylus.  Cretaceous  Ornitho- 
saurs  sometimes  differ  from  birds  apparently  in  ad- 
mitting the  quadrato-jugal  bone  into  the  orbit.  It 
then  becomes  an  expanded  plate,  instead  of  a  slender 
bar  as  in  all  birds. 

THE    TEMPORAL    FOSSA 

A  fourth  vacuity  is  known  as  the  temporal  fossa. 
When  the  skull  of  such  a  mammal  as  a  Rabbit,  or 
Sheep,  is  seen  from  above,  there  is  a  vacuity  behind 
the  orbits  for  the  eyes,  which  in  life  is  occupied  by 
the  muscles  which  work  the  lower  jaw.  It  is  made 
by  the  malar  bone  extending  from  the  back  of  the 
orbit  and  the  process  of  bone,  called  the  zygomatic 
process,  extending  forward  from  the  articulation  of 
the  jaw,  which  arches  out  to  meet  the  malar  bone. 

In  birds  there  is  no  conspicuous  temporal  fossa, 
because  the  malar  bar  is  a  slender  rod  of  bone  in  a 
line  with  the  lower  end  of  the  quadrate  bone. 

Reptile  skulls  have  sometimes  one  temporal  vacuity 
on  each  side,  as  among  tortoises,  formed  by  a  single 
lateral  bar.  These  vacuities,  which  ^correspond  to 
those  of  mammals  in  position,  are  seen  from  the  top 
of  the  head,  as  lateral  vacuities  behind  the  orbits 
of  the  eyes,  and  are  termed  superior  temporal  vacui- 
ties. In  addition  to  these  there  is  often  in  other 


»68  DRAGONS   OF   THE   AIR 

reptiles  a  lateral  opening  behind  the  eye,  termed 
the  inferior  temporal  vacuity,  seen  in  Crocodiles,  in 
Hatteria,  and  in  Lizards  ;  and  in  such  skulls  there  are 
two  temporal  bars  seen  in  side  view,  distinguished  as 
superior  and  inferior.  The  superior  arch  always  in- 
cludes the  squamosal  bone,  which  is  at  the  back 
of  the  single  bar  in  mammals.  The  lower  arch 
includes  the  malar  bone,  which  is  in  front  in  the  single 
arch  of  mammals.  The  circumstance  that  both  these 
arches  are  connected  with  the  quadrate  bone  makes 
the  double  temporal  arch  eminently  reptilian. 

In  Ornithosaurs  the  lateral  temporal  vacuity  varies 
from  a  typically  reptilian  condition  to  one  which, 
without  becoming  avian,  approaches  the  bird  type.  In 
skulls  from  the  Lias,  Dimorphodon  and  Campylogna- 
thus,  there  is  a  close  parallel  to  the  living  New 
Zealand  reptile  Hatteria,  in  the  vertical  position 
of  the  quadrate  bone  and  in  the  large  size  of  the 
vacuity  behind  and  below  the  eye,  which  extends 
nearly  the  height  of  the  skull.  In  the  species  of  the 
genus  Pterodactylus,  the  forward  inclination  of  the 
quadrate  bone  recalls  the  Curlew,  Snipe,  and  other 
birds.  The  back  of  the  head  is  rounded,  and  the 
squamosal  bone,  which  appears  to  enter  into  the 
wall  of  the  brain  case  as  in  birds  and  mammals, 
is  produced  more  outward  than  in  birds,  but  less 
than  in  mammals,  so  as  to  contribute  a  little  to 
the  arch  which  is  in  the  position  of  the  post-frontal 
bone  of  reptiles.  It  is  triangular,  and  stretches  from 
the  outer  angle  of  the  frontal  bone  at  the  back  of  the 
orbit  to  the  squamosal  behind,  where  it  also  meets 
the  quadrate  bone.  Its  third  lower  branch  meets  the 
quadratojugal,  which  rests  upon  the  front  of  the  quad- 
rate bone,  as  in  Iguanodon,  and  is  unlike  Dimorphodon 


THE   PLAN   OF   THE   SKELETON      69 

in  its  connexions.  In  that  genus  the  supra-temporal 
bone,  or  post-orbital  bone,  appears  to  rest  upon  the 
post-frontal  and  connect  it  with  the  quadrato-jugal. 
In  Dimorphodon  the  malar  bone  is  entirely  removed 
from  the  quadrate,  but  in  Pterodactylus  it  meets  its 
articular  end.  Between  the  post-frontal  bone  above 
and  the  quadrato-jugal  bone  below  is  a  small  lunate 
opening,  which  represents  the  lateral  temporal 
vacuity ;  and  so  far,  this  is  a  reptilian  character. 
But  if  the  thin  post-frontal  bone  were  absorbed, 
Pterodactylus  would  resemble  birds.  There  is  no 
evidence  that  the  quadrate  bone  is  free  in  any 
Ornithosaurs,  as  it  is  in  all  birds,  while  in  Dimor- 
phodon it  unites  by  suture  with  the  squamosal  bone. 
In  Ornithostoma  the  lateral  temporal  vacuity  is  little 
more  than  a  slit  between  the  quadrate  bone  below, 
the  quadrato-jugal  in  front,  and  what  may  be  the 
post-frontal  bone  behind  (see  Fig.  2,  p.  12). 

BONES   ABOUT   THE   BRAIN 

The  bones  containing  the  brain  appear  to  be  the 
same  as  form  the  brain  case  in  birds.  The  form  of 
the  back  of  the  skull  varies  in  two  ways.  First  it 
may  be  flat  above  and  flat  at  the  back,  when  the 
back  of  the  head  appears  to  be  square.  This  condi- 
tion is  seen  in  all  the  long-tailed  genera,  such  as 
Campylognathus  from  the  Lias  and  Rhamphorhyn- 
chus,  and  is  associated  with  a  high  position  for  the 
upper  temporal  bar.  Secondly,  the  back  of  the  head 
may  be  rounded  convexly,  both  above  and  behind. 
That  condition  is  seen  in  the  short-tailed  genera, 
such  as  Pterodactylus.  But  in  the  large  Cretaceous 
types,  such  as  Ornithocheirus  and  Ornithostoma, 
the  superior  longitudinal  ridge  which  runs  back  in 


70  DRAGONS    OF   THE   AIR 

the  middle  line  of  the  face  becomes  elevated  and 
compressed  from  side  to  side  at  the  back  of  the  head 
as  a  narrow  deep  crest,  prolonged  backward  over  the 
neck  vertebrae  for  some  inches  of  length.  All  these 
three  types  are  paralleled  more  or  less  in  birds  which 
have  the  back  of  the  head  square  like  the  Heron,  or 
rounded  like  the  Woodpecker;  or  crested,  though  the 
crest  of  the  Cormorant  is  not  quite  identical  with 
Ornithocheirus,  being  a  distinct  bone  at  the  back  of 
the  head  in  the  bird  which  never  blends  with  the 
skull.  In  so  far  as  the  crest  is  reptilian  it  suggests 
the  remarkable  crest  of  the  Chameleon.  In  the 
structure  of  the  back  of  the  skull  the  bones  are  a 
modification  of  the  reptilian  type  of  Hatteria  in 
the  Lias  genus  Campylognathus,  but  the  reptilian 
characters  appear  to  be  lost  in  the  less  perfectly 
preserved  skulls  of  Cretaceous  genera. 

The  palate  is  well  known  in  the  chief  groups  of 
Ornithosaurs,  such  as  Campylognathus,  Scapho- 
gnathus,  and  Cycnorhamphus. 

Mr.  E.  T.  Newton,  F.R.S.,  has  shown  that  in  the 
English  skull  from  the  Lias  of  Whitby,  the  forms  of 
the  bones  are  similar  to  the  palate  in  birds  and  unlike 
the  conditions  in  reptiles.  There  is  one  feature,  how- 
ever, which  may  indicate  a  resemblance  to  Dicynodon 
and  other  fossil  reptiles  from  South  Africa.  A 
slender  bone  extends  from  the  base  of  the  brain  case, 
named  the  basi-sphenoid  bone,  outward  and  forward 
to  the  inner  margin  of  the  quadrate  bone  (Fig.  22). 
A  bone  is  found  thus  placed  in  those  South  African 
Reptiles,  which  show  many  resemblances  to  the  Mono- 
treme  and  Marsupial  Mammals.  It  is  not  an  ordinary 
element  of  the  skeleton  and  is  unknown  in  living 
animals  of  any  kind  in  that  position.  It  has  been 


THE   PLAN   OF   THE   SKELETON       71 

thought  possible  that  it  may  represent  one  of  the 
bones  which  among  mammals  are  diminutive  and 
are  included  in  the  internal  ear.  The  resemblance 
may  have  some  interest  hereafter,  as  helping  to  show 
that  certain  affinities  of  the  Ornithosaurs  may  lie 


Palate  of  the  parrot 
JMacrocercus 


Quadrate 


Restored  palate  of  the  Pterodactyle 
?  Campylognathus 


Quadrate 


Intermaxillary 


outside  the  groups  of  existing  reptiles.  Instead  of 
being  directed  transversely  outward,  as  in  the  palatal 
region  of  Dicynodon  lacerticeps,  they  diverge  out- 
ward and  forward  to  the  inner  border  of  the  articula- 
tion for  the  lower  jaw  which  is  upon  the  quadrate 
bone. 

BONES   OF   THE   PALATE 

There  is  a  pair  of  bones  which  extend  forward 
from  these  inner  articular  borders  of  the  quadrate 
bones,  and  converge  in  a  long  V-shape  till  they 
merge  in  the  hard  palate  formed  by  the  bones  of  the 
front  of  the  beak,  named  intermaxillary  and  maxillary 
bones.  The  limits  of  the  bones  of  the  palate  are 


72  DRAGONS   OF   THE   AIR 

not  distinct,  but  there  can  be  no  doubt  that  the  front 
of  the  V  is  the  bone  named  vomer,  that  the  palatine 
bones  are  at  its  sides,  and  that  its  hinder  parts  are 
the  pterygoid  bones  as  in  birds.  There  is  a  long, 
wide,  four-sided,  open  space  in  the  middle  of  the 
palate,  between  the  vomer  and  the  basi-sphenoid 
bone,  unlike  anything  in  birds  or  other  animals. 

Professor  Marsh,  in  a  figure  of  the  palate  in  the 
great  skull  of  the  toothless  Pterodactyle  named  Orni- 
thostoma  (Pteranodon),  from  the  Chalk  of  Kansas, 
found  a  large  oval  vacuity  in  this  region  of  the  palate. 
In  that  genus  the  pterygoid  bones  meet  each  other 
between  the  quadrate  bones  as  in  Dicynodon  (Fig.  73, 
p.  182).  Hence  the  great  palatal  vacuity  here  seen  in 
the  Ornithosaur  is  paralleled  by  the  small  vacuity  in 
the  South  African  reptile,  which  is  sometimes  distinct 
and  sometimes  partly  separated  from  the  anterior 
part  of  the  vacuity  which  forms  the  openings  of  the 
nostrils  on  the  palate. 

The  Solenhofen  skulls  which  give  any  evidence  of 
the  palate  are  exposed  in  side  view  only,  and  the 
bones,  imperfectly  seen  through  the  lateral  vacuities, 
are  displaced  by  crushing.  They  include  long  strips 
like  the  vomerine  bones  in  the  Lias  fossil,  and  they 
diverge  in  the  same  way  as  they  extend  back  to  the 
quadrate  bones.  The  oblique  division  into  vomer  in 
front  and  pterygoid  bone  behind  is  shown  by  Gold- 
fuss  in  his  original  figure  of  Scaphognathus.  Thus 
there  is  some  reason  for  believing  that  all  Ornithosaurs 
have  the  palate  formed  upon  the  same  general  plan, 
which  is  on  the  whole  peculiar  to  the  group,  especially 
in  not  having  the  palatal  openings  of  the  nares 
divided  in  the  middle  line.  It  would  appear  probable 
that  the  short-tailed  animals  have  the  pterygoid  bones 


THE   PLAN   OF   THE   SKELETON       73 

meeting  in  the  middle  line  and  triangular ;  and  that 
they  are  slender  rods  entirely  separate  from  each 
other  in  the  long-tailed  genera. 

THE   TEETH 

The  teeth  are  all  of  pointed,  elongated  shape,  with- 
out distinction  into  the  kinds  seen  in  most  mammals 
and  named  incisors,  canines,  and  grinders.  They  are 
organs  for  grasping,  like  the  teeth  of  the  fish-eating 
Crocodile  of  India,  and  are  not  unlike  the  simple  teeth 
of  some  Porpoises.  They  are  often  implanted  in 
oblique  oval  sockets  with  raised  borders,  usually  at 
some  distance  apart  from  each  other,  and  have  the 
crown  pointed,  flattened  more  on  the  outer  side  than 
on  the  inner  side,  usually  directed  forward  and  curved 
inward.  As  in  many  extinct  animals  allied  to  exist- 
ing reptiles,  the  teeth  are  reproduced  by  germs,  which 
originate  on  the  inner  side  of  the  root  and  grow  till 
they  gradually  absorb  the  substance  of  the  old  tooth, 
forming  a  new  one  in  its  place.  Frequently  in  Solen- 
hofen  genera,  like  Scaphognathus  and  Pterodactylus, 
the  successional  tooth  is  seen  in  the  jaw  on  the  hinder 
border  of  the  tooth  in  use.  There  is  some  variation 
in  the  character  of  bluntness  or  sharpness  of  the 
crowns  in  the  different  genera,  and  in  their  size. 

The  name  Dimorphodon,  given  to  the  animal  from 
the  Lias  of  Lyme  Regis,  expresses  the  fact  that  the 
teeth  are  of  two  kinds.  In  the  front  of  the  jaw  three  or 
four  large  long  teeth  are  found  in  the  intermaxillary 
bone  on  each  side,  as  in  some  Plesiosaurs,  while  the 
teeth  found  further  back  in  the  maxillary  bone  are 
smaller,  and  directed  more  vertically  downward.  This 
difference  is  more  marked  in  the  lower  jaw  than  in  the 
upper  jaw.  In  Rhamphorhynchus  the  teeth  are  all 


74  DRAGONS   OF   THE   AIR 

relatively  long  and  large,  and  directed  obliquely 
forward,  but  absent  from  the  extremities  of  the  beak, 
as  in  the  German  genus  from  the  Lias  named  Dory- 
gnathus,  in  which  the  bone  of  the  lower  jaw  (which 
alone  is  known)  terminates  in  a  compressed  spear. 
In  Scaphognathus  the  teeth  are  few,  more  vertical, 
and  do  not  extend  backward  so  far  as  in  Rhampho- 
rhynchus,  but  are  carried  forward  to  the  extremity  of 
the  blunt,  deep  jaw. 

In  the  short- tailed  Pterodactyles  the  teeth  are 
smaller,  shorter,  wider  at  the  base  of  the  crown, 
closer  together,  and  do  not  extend  so  far  backward 
in  the  jaw.  'In  Ornithocheirus  two  teeth  always 
project  forward  from  the  front  of  the  jaw.  Ornitho- 
stoma  is  toothless. 

SUPPOSED   HORNY  BEAK 

Sometimes  a  horny  covering  has  been  suggested 
for  the  beak,  like  that  seen  in  birds  or  turtles,  but  no 
such  structure  has  been  preserved,  even  in  the  Solen- 
hofen  Slate,  in  which  such  a  structure  would  seem  as 
likely  to  be  preserved  as  a  wing  membrane,  though 
there  is  one  doubtful  exception.  There  are  marks  of 
fine  blood  vessels  on  some  of  the  jaws,  indicating  a 
tough  covering  to  the  bone.  In  Rhamphorhynchtis 
the  jaws  appear  to  gape  towards  their  extremities  as 
though  the  interspace  had  originally  been  occupied 
by  organic  substance  like  a  horny  beak. 

LOWER  JAW 

The  lower  jaw  varies  in  relative  length  with  the 
vertical  or  horizontal  position  of  the  quadrate  bone  in 
the  skull.  In  Dimorphodon  the  jaw  is  as  long  as  the 
skull  ;  but  in  the  genera  from  the  Oolitic  rocks  the 


THE   PLAN   OF  THE   SKELETON       75 

mandible  is  somewhat  shorter,  and  in  Ormthostoma 
the  discrepancy  reaches  its  maximum.  The  hinder 
part  of  the  jaw  is  never  prolonged  backward  much 
beyond  the  articulation,  differing  in  this  respect  from 
Crocodiles  and  Plesiosaurs. 

The  depth  of  the  jaw  varies.  It  is  slender  in 
Pterodactylus,  and  is  probably  stronger  relatively  to 
the  skull  in  Scaphognathus  than  in  any  other  form. 
It  fits  between  the  teeth  and  bones  of  the  alveolar 
border  in  the  skull,  in  all  the  genera.  In  Dimor- 
phodon  its  hinder  border  is  partly  covered  by  the 
descending  edge  of  the  malar  process  which  these 
animals  develop  in  common  with  some  Dinosaurs, 
and  some  Anomodont  reptiles,  and  many  of  the  lower 
mammals.  In  this  hinder  region  the  lower  jaw  is 
sometimes  perforated,  in  the  same  way  as  in  Croco- 
diles. That  condition  is  observed  in  Dimorphodon, 
but  is  not  found  in  Pterodactylus.  The  lower  jaw  is 
always  composite,  being  formed  by  several  bones,  as 
among  reptiles  and  birds.  The  teeth  are  in  the 
dentary  bone  or  bones,  and  these  bones  are  almost 
always  blended  as  in  most  birds  and  Turtles,  and  not 
separate  from  each  other  as  among  Crocodiles,  Lizards, 
and  Serpents. 

An  interesting  contour  for  the  lower  border  of  the 
jaw  is  seen  in  Ornithostoma,  as  made  known  in 
figures  of  American  examples  by  Professors  Marsh 
and  Williston.  It  deepens  as  it  extends  backwards 
for  two-thirds  its  length,  stops  at  an  angle,  and  then 
the  depth  diminishes  to  the  articulation  with  the 
skull.  This  angle  of  the  lower  jaw  is  a  characteristic 
feature  of  the  jaws  of  Mammals.  It  is  seen  in  the 
monotreme  Echidna,  and  is  characteristic  of  some 
Theriodont  Reptiles  from  South  Africa,  which  in 


76 


DRAGONS   OF  THE   AIR 


many  ways  resemble  Mammals.      The  character  is 
not  seen  in  the  jaws  of  specimens  from  the  Oolitic 


Ornithostoma 


Seen  from  above 


FIG.  23.      COMPARISON   OF  THE   LOWER  JAW   IN 
ECHIDNA  AMD   ORNITHOSTOMA 


rocks,  but  is  developed  in  the  toothed  Ornithocheirus 
from  the  Cambridge  Greensand,  and  is  absent  from 
the  jaws  of  existing  reptiles  and  birds. 

SUMMARY  OF  CHARACTERS  OF  THE  HEAD 
Taken  as  a  whole,  the  head  differs  from  other  types 
of  animals  in  a  blending  of  characters  which  at  the 
present  day  are  found  among  Birds  and  Reptiles,  with 
some  structures  which  occur  in  extinct  groups  of 
animals  with  similar  affinities,  and  perhaps  a  slight 
indication  of  features  common  to  the  lowest  mammals. 
It  is  chiefly  upon  the  head  that  the  diverse  views  of 
earlier  writers  have  been  based.  Cuvier  was  im- 
pressed with  the  reptilian  aspect  of  the  teeth  ;  but  in 
later  times  discoveries  were  made  of  Birds  with  teeth 
— Archaeopteryx,  Ichthyornis,  Hesperornis.  The  teeth 
are  quite  reptilian,  being  not  unlike  miniature  teeth 


THE   PLAN   OF   THE   SKELETON       77 

of  Mosasaurus.  If  those  birds  had  been  found  prior 
to  the  discovery  of  Pteroclactyles,  the  teeth  might 
have  been  regarded  as  a  link  with  the  more  ancient 
birds,  rather  than  a  crucial  difference  between  birds 
and  reptiles. 

All  the  specimens  show  a  lateral  temporal  hole  in 
the  bones  behind  the  eye,  and  this  is  found  in  no 
bird  or  mammal,  and  is  typical  of  such  reptiles  as 
Hatteria.  The  quadrate  bone  may  not  be  so  decisive 
as  Cuvier  thought  it  to  be,  for  its  form  is  not  unlike 
the  quadrate  of  a  bird,  and  different,  so  far  as  I  have 
seen,  from  that  of  living  reptiles.  This  region  of  the 
head  is  reptilian,  and  if  it  occurred  in  a  bird  the  cha- 
racter would  be  as  astonishing  as  was  the  discovery  of 
teeth  in  extinct  birds.  These  characters  of  the  head 
are  also  found  in  fossil  animals  named  Dinosaurs,  in 
association  with  many  resemblances  to  birds  in  their 
bones. 

The  palate  might  conceivably  be  derived  from 
that  of  Hatteria  by  enlarging  the  small  opening  in 
the  middle  line  in  that  reptile  till  it  extended  forward 
between  the  vomera ;  but  it  is  more  easily  compared 
with  a  bird,  which  the  animal  resembles  in  its  beak, 
and  in  the  position  of  the  nares.  Excepting  certain 
Lizards,  all  true  existing  Reptiles  have  the  nostrils 
far  forward  and  bordered  by  two  premaxillary  bones 
instead  of  one  intermaxillary,  as  in  Birds  and  Or- 
nithosaurs.  If  nothing  were  known  of  the  animal  but 
its  head  bones,  it  would  be  placed  between  Reptiles 
and  Birds. 


CHAPTER    IX 

THE    BACKBONE,    OR    VERTEBRAL 
COLUMN 

THE  backbone  is  a  more  deep-seated  part  of  the 
skeleton  than  the  head.  It  is  more  protected 
by  its  position,  and  has  less  varied  functions  to  per- 
form. Therefore  it  varies  less  in  distinctive  character 
within  the  limits  of  each  of  the  classes  of  vertebrate 
animals  than  either  the  head  or  limbs.  It  is  divided 
into  neck  bones,  the  cervical  vertebrae ;  back  bones, 
the  dorsal  vertebrae  ;  loin  bones,  the  lumbar  vertebrae  ; 
the  sacrum,  or  sacral  vertebrae,  which  support  the 
hind  limbs  ;  and  the  tail.  Of  these  parts  the  tail  is 
the  least  important,  though  it  reaches  a  length  in 
existing  reptiles  which  sometimes  exceeds  the  whole 
of  the  remainder  of  the  body,  and  includes  hundreds 
of  vertebrae.  It  attains  its  maximum  among  serpents 
and  lizards.  In  frogs  it  is  practically  absent.  In 
some  of  the  higher  mammals  it  is  a  rudiment,  which 
does  not  extend  beyond  the  soft  parts  of  the  body. 

THE   NECK 

The  neck  is  more  liable  to  vary  than  the  back,  with 
the  habit  of  life  of  the  animal.  And  although 
mammals  almost  always  preserve  the  same  number 

78 


THE   BACKBONE  79 

of  seven  bones  in  the  neck,  the  bones  vary  in  length 
between  the  short  condition  of  the  porpoise,  in 
which  the  neck  is  almost  lost,  and  the  long  bones 
which  form  the  neck  of  the  Llama,  though  even  these 
may  be  exceeded  by  some  fossil  reptiles  like  Tany- 
strophceus.  In  many  mammals  the  neck  bones  do 
not  differ  in  length  or  size  from  those  of  the  back. 
In  others,  like  the  Horse  and  Ox,  they  are  much 
broader  and  larger. 

There  is  the  same  sort  of  variation  in  the  bones  of 
the  neck  among  birds,  some  being  slender  like  the 
Heron,  others  broad  like  the  Swan.  But  there  is  also 
a  singular  variation  in  number  of  vertebral  bones 
in  a  bird's  neck.  At  fewest  there  are  nine,  which 
equals  the  exceptionally  large  number  found  among 
mammals  in  the  neck  of  one  of  the  Sloths.  Usually 
birds  have  ten  to  fifteen  cervical  vertebrae,  and  in  the 
Swan  there  are  twenty-three.  Most  of  the  neck  bones 
of  birds  are  relatively  long,  and  the  length  of  the  neck 
is  often  greater  than  the  remainder  of  the  vertebral 
column. 

Reptiles  usually  have  short  necks.  The  common 
Turtle  has  eight  bones  in  the  neck,  ten  in  the  back. 
The  two  regions  are  sharply  defined  by  the  dorsal 
shield.  Their  articular  ends  are  sometimes  cupped  in 
front,  in  the  neck,  sometimes  cupped  behind,  or  con- 
vex at  both  ends,  or  even  flattened,  or  the  articulation 
may  be  made  exceptionally  by  the  neural  arch  alone. 
Nine  is  the  largest  number  of  neck  bones  in  existing 
Lizards,  and  there  -are  usually  nine  in  Crocodiles ;  so 
that  reptiles  closely  approach  mammals  in  number  of 
the  neck  bones.  It  is  remarkable  that  the  maximum 
number  in  a  mammal  and  in  living  reptiles  should 
coincide  with  the  minimum  number  in  birds.  There- 


8o  DRAGONS   OF   THE   AIR 

fore  the  number  of  cervical  vertebrae  as  an  attribute 
of  Mammal,  Bird,  or  Reptile,  can  only  be  important 
from  its  constancy. 

German  naturalists  affirm  on  clear  evidence  that 
the  Solenhofen  Pterodactyles  have  seven  cervical  ver- 
tebrae. In  many  specimens  there  can  be  no  doubt 
about  the  number,  because  the  neck  bones  are  easily 
distinguished  from  those  of  the  back  by  their  size ; 
but  the  number  is  not  always  easy  to  count 

As  in  Birds,  the  first  vertebra,  or  atlas,  in  Pterodac- 
tyles is  extremely  short,  and  is  generally — if  not 
always — blended  with  the  much  longer  second  ver- 
tebra, named  the  axis.  The  front  of  the  atlas  forms 
a  small  rounded  cup  to  articulate  with  the  rounded 
ball  of  the  basioccipital  bone  at  the  back  of  the  skull. 
The  third  and  fourth  vertebras  are  longer,  but  the 
length  visibly  shortens  in  the  sixth  and  seventh. 

Sometimes  the  vertebrae  are  slender  and  devoid  of 
strong  spinous  processes.  This  is  the  condition  in 
the  little  Pterodactylus  longirostris  and  in  the  com- 
paratively large  Cycnorhamphus  Fraasii,  in  which 
there  is  a  slight  median  ridge  along  the  upper  surface 
of  the  arch  of  the  vertebra.  This  condition  is  paral- 
leled in  birds  with  long  necks,  especially  wading 
birds  such  as  the  Heron.  Other  Ornithosaurs,  such 
as  Ornithocheirus  from  the  Cretaceous  rocks,  have  the 
neck  much  more  massive.  The  vertebrae  are  flattened 
on  the  under  side.  The  arch  above  the  nervous 
matter  of  the  spinal  cord  has  a  more  or  less  con- 
siderable transverse  expansion,  and  may  even  be  as 
wide  as  long.  These  vertebrae  have  proportions  and 
form  such  as  may  be  seen  in  Vultures  or  in  the 
Swan.  In  either  case  the  form  of  the  neck  bones 
is  more  or  less  bird-like,  and  the  neural  spine  may 


THE    BACKBONE 


Hi 


be  elevated,  especially  in  Pterodactyles  with  long 
tails. 

One  of  the  most  distinctive  features  of  the  neck 
bones  of  a  bird  is  the  way  in  which  the  cervical  ribs 
are  blended  with  the  vertebrae.  They  are  small,  and 
each  is  often  prolonged  in  a  needle-like  rod  at  the 
side  of  the  neck  bone. 

In  Ornithocheirus  the  cervical  rib  similarly  blends 
with  the  vertebra  by  two  articulations,  as  in  mam- 
mals, so  that  it  might  escape  notice  but  for  the 
channel  of  a  blood  vessel  which  is  thus  inclosed. 
In  several  of  the  older  Pterodactyles  from  Solen- 
hofen  the  ribs  of  the  neck  vertebrae  remain  sepa- 
rated, as  in  a  Crocodile,  though  still  bird-like  in  their 
form,  anterior  position,  and  mode  of  attachment.  In 
Terrapins  and  Tortoises  the  long  neck  vertebrae  have 
no  cervical  ribs. 

The  articular  surfaces  between  the  bodies  of  the 
vertebrae,  in  the  neck,  are  transversely  oval.  The  middle 

Front  Back  Left  side 


FIG.  24 

UNITED  ATLAS  AND  AXIS  OF  ORNITHOCHEIRUS 
(Cambridge  Greensand) 

part  of  this  articular  joint  is  made  by  the  body  of 
the  vertebra;  its  outer  parts  are  in  the  neural  arch. 
In  front  this  surface  is  a  hollow  channel,  often  more 
depressed  than  in  any  other  animals.  The  corre- 
sponding surface  behind  is  convex,  with  a  process  on 
G 


82  DRAGONS    OF   THE   AIR 

each  side  at  its  lower  outer  angles  (Fig.  25).  It  is  a 
modification  of  the  cup-and-ball  form  of  vertebral 
articulation,  which  at  the  present  day  is  eminently 
reptilian.  Serpents  and  Crocodiles  have  the  articu- 
lations similarly  vertical,  but  in  both  the  form  of  the 
articulation  is  a  circle.  In  Lizards  the  articular  cup  is 
usually  rather  wider  than  deep,  when  the  cup  and 
ball  are  developed  in  the  vertebrae  ;  it  differs  from 
the  vertical  condition  in  pterodactyles  in  being  oblique 
and  much  narrower  from  side  to  side.  Only  among 
Crocodiles  and  Hatteria  is  there  a  double  articulation 
for  the  cervical  rib,  though  in  neither  order  have  rib 
or  vertebra  in  the  neck  the  bird  -  like  proportions 
which  are  usual  in  these  animals.  Pterodactyles  show 
no  resemblance  to  birds  in  this  vertebral  articulation. 
A  Bird  has  the  corresponding  surface  concave  from 
side  to  side  in  front,  but  it  is  also  convex  from  above 
downward,  producing  what  is  known  as  the  saddle- 
shaped  form  which  is  peculiarly  avian,  being  found 
in  existing  birds  except  in  part  of  the  back  in  Pen- 
guins. It  is  faintly  approximated  to  in  one  or  two 
neck  vertebrae  in  man.  Professor  Williston  remarks 
that  in  the  toothless  Pterodactyles  of  Kansas  the 
hinder  ball  of  the  vertebral  articulation  is  continued 
downward  and  outward  as  a  concave  articulation 
upon  the  processes  at  its  outer  corners.  There  are 
no  mammals  with  a  cup-and-ball  articulation  between 
the  vertebrae,  so  that  for  what  it  is  worth  the  char- 
acter now  described  in  Ornithosaurs  is  reptilian,  when 
judged  by  comparison  with  existing  animals. 

Low  down  on  each  side  of  the  vertebra,  at  the 
junction  of  its  body  with  the  neural  arch,  is  a  large 
ovate  foramen,  transversely  elongated,  and  often  a 
little  impressed  at  the  border,  which  is  the  entrance 


THE    BACKBONE  83 

of  the  air  cell  into  the  bone.  These  foramina  are 
often  one-third  of  the  length  of  the  neck  vertebrae 
in  specimens  from  the  Cambridge  Greensand,  where 
the  neck  bones  vary  from  three-quarters  of  an  inch 
to  about  two  and  a  half  inches  in  length,  and  in 
extreme  forms  are  as  wide  as  long.  The  width  of 
the  interspace  between  the  foramina  is  one-half  the 
width  of  the  vertebrae,  though  this  character  varies 
with  different  genera  and  species.  Several  species 


Seen  from  below      1\  \\  I1         [/     Seen  from  above 


FIG.  25.      CERVICAL  VERTEBRA  OF  ORNITHOCHEIRUS 
From  the  Cambridge  Greensand 

from  the  Solenhofen  Slate  have  the  neck  long  and 
slender,  on  the  type  of  the  Flamingo.  In  others  the 
neck  is  thick  and  short — in  the  Scaphognathus  crassi- 
rostris  and  Pterodactylus  spectabilis.  Some  genera 
with  slender  necks  have  the  bones  preserved  with  a 
curved  contour,  such  as  might  suggest  a  neck  carried 
like  that  of  a  Llama  or  a  Camel.  The  neck  is  occa- 
sionally preserved  in  a  curve  like  a  capital  S,  as 
though  about  to  be  darted  forward  like  that  of  a 
bird  in  the  act  of  striking  its  prey.  The  genera  of 
Pterodactyles  with  short  necks  may  have  had  as  great 
mobility  of  neck  as  is  found  among  birds  named 
Ducks  and  Divers ;  but  those  Pterodactyles  with 
stout  necks,  such  as  Dimorphodon  and  Ornitho- 
cheirus,  in  which  the  vertebrae  are  large,  appear  to 


84  DRAGONS   OF   THE   AIR 

have  been  built  more  for  strength  than  activity,  and 
the  neck  bones  have  been  chiefly  concerned  in  the 
muscular  effort  to  use  the  fighting  power  of  the  jaws 
in  the  best  way. 

THE   BACK 

The  region  of  the  back  in  a  Pterodactyle  is  short 
as  compared  with  the  neck,  and  relatively  is  never 
longer  than  the  corresponding  region  in  a  bird.  The 
shortness  results  partly  from  the  short  length  of  the 
vertebrae,  each  of  which  is  about  as  long  as  wide. 
There  is  also  a  moderate  number  of  bones  in  the 
back.  In  most  skeletons  from  Solenhofen  these 
vertebrae  between  the  neck  and  girdle  of  hip  bones 
number  from  twelve  to  sixteen.  They  have  a  general 
resemblance  in  form  to  the  dorsal  vertebrae  in  birds. 
The  greatest  number  of  such  vertebrae  in  birds  is 
eleven.  The  number  is  small  because  some  of  the 
later  vertebrae  in  birds  are  overlapped  by  the  bones 
of  the  hip  girdle,  which  extend  forward  and  cover 
them  at  the  sides,  so  that  they  become  blended  with 
the  sacrum.  This  region  of  the  skeleton  in  the 
Dimorphodon  from  the  Lias  is  remarkable  for  the 
length  of  the  median  process,  named  the  neural 
spine,  which  is  prolonged  upward  like  the  spines  of 
the  early  dorsal  vertebrae  of  Horses,  Deer,  and  other 
mammals.  In  this  character  they  differ  from  living 
reptiles,  and  parallel  some  Dinosaurs  from  the  Weald. 
The  bones  of  the  back  in  Ornithocheirus  from  the 
Cambridge  Greensand  show  the  under  side  to  be  well 
rounded,  so  that  the  articular  surfaces  between  the 
vertebrae,  though  still  rather  wider  than  deep,  are 
much  less  depressed  than  in  the  region  of  the  neck. 
The  neural  canal  for  the  spinal  cord  has  become 


THE   BACKBONE  85 

larger  and  higher,  and  the  sides  of  the  bone  are 
somewhat  compressed.  Strong  transverse  processes 
for  the  support  of  the  ribs  are  elevated  above  the 
level  of  the  neural  canal,  at  the  sides  of  vertebras 
compressed  on  the  under  sides,  and  directed  out- 
ward. Between  these  lateral  horizontal  platforms 
is  the  compressed  median  neural  spine,  which  varies 
in  vertical  height.  The  articulation  of  the  ribs  is  not 
seen  clearly.  Isolated  ribs  from  the  Stonesfield  Slate 
have  double-headed  dorsal  ribs,  like  those  of  birds. 
In  some  specimens  from  the  Solenhofen  Slate  like 
the  Scaphognathus,  in  the  University  Museum  at 
Bonn,  dorsal  ribs  appear  to  be  attached  by  a  notch 
in  the  transverse  process  of  the  dorsal  vertebra,  which 
resembles  the  condition  in  Crocodiles.  Variations  in 
the  mode  of  attachment  of  ribs  among  mammals 
may  show  that  character  to  be  of  subordinate  im- 
portance. Von  Meyer  has  described  the  first  pair 
of  ribs  as  frequently  larger  than  the  others,  and 
there  appear  in  Rhamphorhynchus  to  be  examples 
preserved  of  the  sternal  ribs,  which  connect  the 
dorsal  ribs  with  the  sternum.  Six  pairs  have  been 
counted.  A  more  interesting  feature  in  the  ribs 
consists  in  the  presence  behind  the  sternum,  which 
is  shorter  than  the  corresponding  bone  in  most  birds, 
of  median  sternal  ribs.  They  are  slender  V-shaped 
bones  in  the  middle  line  of  the  abdomen,  which 
overlapped  the  ends  of  the  dorsal  ribs  like  the 
similar  sternal  bones  of  reptiles.  Such  structures 
are  unknown  among  Birds  and  Mammals.  There  is 
no  trace  in  the  dorsal  ribs  of  the  claw-like  process, 
which  extends  laterally  from  rib  to  rib  as  a  marked 
feature  in  many  birds.  Its  presence  or  absence  may 
not  be  important,  because  it  is  represented  by  fibre- 


86  DRAGONS   OF  THE   AIR 

cartilage  in  the  ribs  of  crocodiles,  and  may  be  a  small 
cartilage  near  the  head  of  the  rib  in  serpents,  and  is 
only  ossified  in  some  ribs  of  the  New  Zealand  reptile 


FIG.  26 

The  upper  figures  show  the  side  and  back  of  a  dorsal  vertebra  of 

Ornithocheirus  compared  with  corresponding  views  of  the 

side  and  back  of  a  dorsal  vertebra  of  a  Crocodile 

Hatteria.  So  that  it  might  have  been  present  in  a 
fossil  animal  without  being  ossified  and  preserved. 
Although  the  structure  is  associated  with  birds,  it 
is  possibly  also  represented  by  the  great  bony  plates 
which  cover  the  ribs  in  Chelonians,  and  combine  to 
form  the  shield  which  covers  the  turtle's  back.  The 
structure  is  as  characteristic  of  reptiles  as  of  birds, 
but  is  not  necessarily  associated  with  either. 

There  are  two  remarkable  modifications  of  the 
early  dorsal  vertebrae  in  some  of  the  Cretaceous 
Pterodactyles.  First,  in  the  genus  Ornithodesmus 
from  the  Weald  the  early  dorsal  vertebrae  are  blended 
together  into  a  continuous  mass,  like  that  which  is 
found  in  the  corresponding  region  of  the  living 
Frigate-bird,  only  more  consolidated,  and  similar  to 


THE    BACKBONE  87 

that  consolidated  structure  found  behind  the  dorsal 
vertebrae,  known  as  the  sacrum,  made  by  the  blending 
of  the  vertebrae  into  a  solid  mass  which  supports 
the  hip  bones.  Secondly,  in  some  of  the  Cretaceous 
genera  of  Pterodactyles  of  Europe  and  America  the 
vertebrae  in  the  front  part  of  the  back  are  similarly 
blended,  but  their  union  is  less  complete  ;  and  in 
genera  Ornithocheirus  and  Ornithostoma — the  former 
chiefly  English,  the  latter  chiefly  American — the 
sides  of  the  neural  spines  are  flattened  to  form  an 
oval  articular  surface  on  each  side,  which  gives 
attachment  to  the  flattened  ends  of  their  shoulder- 
blade  bones  named  the  scapulae.  This  condition  is 
found  in  no  other  animals.  Three  vertebrae  appear 
to  have  their  neural  arches  thus  united  together. 
The  structure  so  formed  may  be  named  the  notarium 
to  distinguish  it  from  the  sacrum. 

SACRUM 

For  some  mysterious  reason  the  part  of  the  back- 
bone which  lies  between  the  bones  of  the  hips  and 
supports  them  is  termed  the  sacrum.  Among  living 
reptiles  the  number  of  vertebrae  in  this  region  is 
usually  two,  as  in  lizards  and  crocodiles.  There  are 
other  groups  of  fossil  reptiles  in  which  the  number 
of  sacral  vertebrae  is  in  some  cases  less  and  in  other 
cases  more.  There  is,  perhaps,  no  group  in  which  the 
sacrum  makes  a  nearer  approach  to  that  of  birds 
than  is  found  among  these  Pterodactyles,  although 
there  are  more  sacral  vertebras  in  some  Dinosaurs. 
In  birds  the  sacral  vertebrae  number  from  five  to 
twenty-two.  In  bats  the  number  is  from  five  to  six. 
In  some  Solenhofen  species,  such  as  Pterodactylus 
dubius  and  P.  Kochi  and  P.  grandipehis,  the  number 


88  DRAGONS   OF   THE   AIR 

is  usually  five  or  six.     The  vertebrae  are  completely 
blended.     The  pneumatic  foramina  in  the  sacrum,  so 
far  as  they  have  been  observed,  are  on  the  under 
sides  of  the  transverse  processes ; 
while  in  the  corresponding  no- 
tarial structure  in  the  shoulder 
girdle  the  foramina  are  in  front 
of  the  transverse  processes.    Al- 
most any  placental  mammal  in 
which  the  vertebrae  of  the  sacral 
region  are  anchylosed  together 
has    a    similar    sacrum,    which 
differs  from  that  of  birds  in  the 
more  complete  individuality  of 
the  constituent  bones  remaining 
KIG.  27.    SACRUM  OF      evident.      The    transverse    pro- 
RHAMPHORHYNCHUS       cesses  in  front  of  the  sacrum  are 

Showing  the  complete  blend-  •  i         ,  i  •        t   •      i 

ing  of  the  vertebra  and  ribs  as  wider  than  in  its  hinder  part ;  so 
iL^net'^oduTerctry  that  the  pelvic  bones  which  are 
attached  to  »t  converge  as  they 
extend  backward,  as  among 
mammals.  The  bodies  of  the  vertebra  forming  the 
sacrum  are  similar  in  length  to  those  of  the  back. 
Each  transverse  process  is  given  off  opposite  the 
body  of  its  own  vertebra,  but  from  a  lower  lateral 
position  than  in  the  region  of  the  back,  in  which  the 
vertebrae  are  free. 

The  hip  bones  are  closely  united  with  the  sacrum 
by  bony  union,  and  rarely  appear  to  come  away  from 
the  sacral  vertebrae,  as  among  mammals  and  reptiles, 
though  this  happens  with  the  Lias  Pterodactyles.  In 
the  Stonesfield  Slate  and  Solenhofen  Slate  the  slender 
transverse  processes  from  the  vertebrae  blend  with  the 
ilium  of  the  hip  girdle,  and  form  a  series  of  trans- 


THE   BACKBONE  89 

verse  foramina  on  each  side  of  the  bodies  of  the  verte- 
brae. In  the  Cambridge  Greensand  genera  the  part 
of  the  ilium  above  the  acetabulum  for  the  articular 
head  of  the  femur  appears  to  be  always  broken  away, 
so  that  the  relation  of  the  sacrum  to  the  pelvis  has 
not  been  observed.  This  character  is  no  mark  of 
affinity,  but  only  shows  that  ossification  obliterated 
sutures  among  these  animals  in  the  same  way  as 
among  birds. 

The  great  difference  between  the  sacrum  of  a 
Pterodactyle  and  that  of  a  bird  has  been  rendered 
intelligible  by  the  excellent  discussion  of  the  sacral 
region  in  birds  made  by  Professor  Huxley.  He 
showed  that  it  is  only  the  middle  part  of  the  sacrum 
of  a  chicken  which  corresponds  to  the  true  sacrum  of 
a  reptile,  and  comprises  the  five  shortest  of  the  verte- 
bra ;  while  the  four  in  front  correspond  to  those  of 
the  lower  part  of  the  back,  which  either  bear  no  ribs 
or  very  short  ribs,  and  are  known  as  the  lumbar 
region  in  mammals,  so  that  the  lower  part  of  the 
back  becomes  blended  with  the  sacrum,  and  thus 
reduces  the  number  of  dorsal  vertebrae.  Similarly 
the  five  vertebras  which  follow  the  true  sacral  verte- 
bra; are  originally  part  of  the  tail,  and  have  been 
blended  with  the  other  vertebrae  in  front,  in  conse- 
quence of  the  extension  along  them  of  the  bird's 
hip  bones.  This  interpretation  helps  to  account  for 
the  great  length  of  the  sacrum  in  many  birds,  and 
also  explains  in  part  the  singular  shortness  of  the 
tail  in  existing  birds.  The  Ornithosaur  sacrum  has 
neither  the  lumbar  nor  the  caudal  portions  of  the 
sacrum  of  a  bird. 


90  DRAGONS   OF   THE   AIR 


THE   TAIL 

The  tail  is  perhaps  the  least  important  part  of  the 
skeleton,  since  it  varies  in  character  and  length  in 
different  genera.  The  short  tails  seen  in  typical 
pterodactyles  include  as  few  as  ten  vertebrae  in 
Pterodactylus  grandipelvis  and  P.  Kochi,  and  as  many 
as  fifteen  vertebrae  in  Pterodactylus  longirostris.  The 
tails  are  more  like  those  of  mammals  than  existing 
birds,  in  which  there  are  usually  from  six  to  ten 
vertebrae  terminating  in  the  ploughshare  bone.  But 
just  as  some  fossil  birds,  like  the  Archaeopteryx,  have 
about  twenty  long  and  slender  vertebrae  in  the  tail, 
so  in  the  pterodactyle  Rhamphorhynchus  this  region 
becomes  greatly  extended,  and  includes  from  thirty- 
eight  to  forty  vertebrae.  In  Dimorphodon  the  tail 
vertebrae  are  slightly  fewer.  The  earliest  are  very 
short,  and  then  they  become  elongated  to  two  or 
three  times  the  length  of  the  early  tail  vertebrae,  and 
finally  shorten  again  towards  the  extremity  of  the 
tail,  where  the  bones  are  very  slender.  In  all  long- 
tailed  Ornithosaurians  the  vertebrae  are  supported 
and  bordered  by  slender  ossified  ligaments,  which 
extend  like  threads  down  the  tail,  just  as  they  do 
in  Rats  and  many  other  mammals  and  in  some 
lizards. 

Professor  Marsh  was  able  to  show  that  the  ex- 
tremity of  the  tail  in  Rhamphorhynchus  sometimes 
expands  into  a  strong  terminal  caudal  membrane  of 
four-sided  somewhat  rhomboidal  shape.  He  regards 
this  membrane  as  having  been  placed  vertically.  It 
is  supported  by  delicate  processes  which  represent 
the  neural  spines  of  the  vertebrae  prolonged  upward. 
They  are  about  fifteen  in  number.  A  corresponding 


THE   BACKBONE  91 

series  of  spines  on  the  lower  border,  termed  chevron 
bones,  equally  long,  were  given  off  from  the  junctions 
of  the  vertebrae  on  their  under  sides,  and  produced 
downward.  This  vertical  appendage  is  of  some 
interest  because  its  expansion  is  like  the  tail  of  a 
fish.  It  suggests  the  possibility  of  having  been  used 
in  a  similar  way  to  the  caudal  fin  as  an  organ  for 
locomotion  in  water,  though  it  is  possible  that  it  may 
have  also  formed  an  organ  used  in  flight  for  steering 
in  the  air. 

The  tail  vertebrae  from  the  Cambridge  Greensand 
are  mostly  found  isolated  or  with  not  more  than  four 


FIG.    28.       EXTREMITY    OF    THE    TAIL    OF 

RHAMPHORHYNCHUS   PHYLLURUS  (MARSH) 

Showing  the  processes  on  the  upper  and  under  sides  of  the  vertebrae 

which  make  the  terminal  leaf-like  expansion 

jo'ints  in  association.  They  are  very  like  the  slender 
type  of  neck  vertebrae  seen  in  long-necked  ptero- 
dactyles,  but  are  depressed,  and  though  somewhat 
wider  are  not  unlike  the  tail  vertebrae  of  the  Rham- 
phorhynchus.  The  pneumatic  foramen  in  them  is  a 
mere  puncture.  They  have  no  transverse  processes 
or  neural  spines,  nor  indications  of  ribs,  or  chevron 
bones. 

The  hindermost  specimens  of  tail  vertebrae  observed 
have  the  neural  arch  preserved  to  the  end,  as  among 
reptiles ;  whereas  in  mammals  this  arch  becomes 
lost  towards  the  end  of  the  tail.  The  processes 
by  which  the  vertebrae  are  yoked  together  are 


92  DRAGONS   OF  THE   AIR 

small.  There  is  nothing  to  suggest  that  the  tail  was 
long,  except  the  circumstance  that  the  slender  caudal 
vertebrae  are  almost  as  long  as  the  stout  cervical 
vertebrae  in  the  same  animal.  No  small  caudal 
vertebrae  have  ever  been  found  in  the  Cambridge 
Greensand.  The  tail  is  very  short,  according  to 
Professor  Williston,  in  the  toothless  Ornithostoma 
in  the  Chalk  of  Kansas. 


CHAPTER   X 

THE    HIP-GIRDLE    AND    HIND 
LIMB 

THE  bones  of  the  hip-girdle  form  a  basin  which 
incloses  and  protects  the  abdominal  vital  organs. 
It  consists  on  each  side  of  a  composite  bone,  the 
unnamed  bones — ossa  innominata  of  the  older  anato- 
mists— which  are  each  attached  to  the  sacrum  on 
their  inner  side,  and  on  the  outer  side  give  attach- 
ment to  the  hind  limbs.  As  a  rule  three  bones  enter 
into  the  borders  of  this  cup,  termed  the  acetabulum,  in 
which  the  head  of  the  thigh  bone,  named  the  Femur, 
moves  with  a  more  or  less  rotary  motion. 

There  are  a  few  exceptions  in  this  division  of  the 
cup  between  three  bones,  chiefly  among  Salamanders 
and  certain  Frogs.  In  Crocodiles  the  bone  below  the 
acetabular  cup  is  not  divided  into  two  parts.  And 
in  certain  Plesiosaurs  from  the  Oxford  Clay — Muraeno- 
saurus — the  actual  articulation  appears  to  be  made 
by  two  bones — the  ilium  and  ischium.  The  three 
bones  which  form  each  side  of  the  pelvis  are  known 
as  the  ilium,  or  hip  bone,  sometimes  termed  the  aitch 
bone ;  secondly,  the  ischium,  or  sitz  bone,  being  the 
bone  by  which  the  body  is  supported  in  a  sitting 
position ;  and  thirdly  the  pubis,  which  is  the  bone  in 
93 


94  DRAGONS   OF   THE   AIR 

front  of  the  acetabulum.  The  pubic  bones  meet  in 
the  middle  line  of  the  body  on  the  under  side  of  the 
pelvis  in  man,  and  on  each  side  are  partly  separated 
from  the  ischia  by  a  foramen,  spoken  of  as  the 
obturator  foramen,  which  in  Pterodactyles  is  minute 
and  almost  invisible,  when  it  exists. 

There  is  often  a  fourth  bony  element  in  the  pelvis. 
In  some  Salamanders  a  single  cartilage  is  directed 
forward,  and  forked  in  front.  According  to  Professor 
Huxley  something  of  this  kind  is  seen  in  the  Dog. 
The  pair  of  bones  which  extend  forward  in  front 
of  the  pelvis  in  Crocodiles  may  be  of  the  same  kind, 
in  which  case  they  should  be  called  prepubic  bones. 
But  among  the  lower  mammals  named  marsupials 
a  pouch  is  developed  for  the  protection  of  the  young 
and  supported  by  two  slender  bones  attached  to  the 
pubes,  and  these  bones  have  long  been  known  as 
marsupial  bones.  In  a  still  lower  group  of  mammalia 
named  monotremata,  which  lay  eggs,  and  in  many 
ways  approximate  to  reptiles  and  birds,  stronger 
bones  are  developed  on  the  front  edge  of  the  pubes, 
and  termed  prepubic  bones.  They  do  not  support  a 
marsupium. 

Naturalists  have  been  uncertain  as  to  the  number 
of  bones  in  the  pelvis  of  Pterodactyles,  because  the 
bones  blend  together  early  in  life,  as  in  birds.  Some 
follow  the  Amphibian  nomenclature,  and  unite  the 
ischium  and  pubis  into  one  bone,  which  is  then 
termed  ischium,  when  the  prepubis  is  termed  the 
pubis,  and  regarded  as  removed  from  the  acetabulum. 
There  is  no  ground  for  this  interpretation,  for  the 
sutures  are  clear  between  the  three  pelvic  bones  in 
the  acetabulum  in  some  specimens,  like  Cycnorham- 
phus  Fraasii,  from  Solenhofen,  and  some  examples 


THE   HIP-GIRDLE  AND    HIND    LIMB     95 

of  Ornithocheirus  from  the  Cambridge  Greensand. 
Pterodactyles  all  have  prepubic  bones,  which  are 
only  known  in  Ornithorhynchus  and  Echidna  among 
mammals,  and  are  absent  from  the  higher  mammals 
and  birds.  They  are  unknown  in  any  other  existing 
animals,  unless  present  in  Crocodiles,  in  which  ischium 
and  pubis  are  always  undivided.  Therefore  it  is 
interesting  to  examine  the  characters  of  the  Ornitho- 
saurian  pelvis. 

The  acetabulum  for  the  head  of  the  femur  is  im- 
perforate,  being  a  simple  oval  basin,  as  in  Chelonian 
reptiles  and  the  higher  Mammals.  It  never  shows 
the  mark  of  the  ligamentous  attachment  to  the  head 
of  the  femur,  which  is  seen  in  Mammals.  In  Birds 
the  acetabulum  is  perforated,  as  in  many  of  the  fossils 
named  Dinosaurs,  and  in  Monotremata. 

Secondly,  the  ilium  is  elongated,  and  extends  quite 
as  much  in  front  of  the  acetabulum  as  behind  it. 


Apteryx  Rhamphorhynchus 


FIG.  29.      COMPARISON   OF  THE   LEFT   SIDE   OF  THE 
PELVIS    IN   A   BIRD   AND   A   PTERODACTYLE 

The  bone  is  not  very  deep  in  this  front  process. 
Among  existing  animals  this  relation  of  the  bone  is 
nearer  to  birds  than  to  any  other  type,  since  birds 
alone  have  the  ilium  extended  from  the  acetabulum 
in  both  directions.  The  form  of  the  Pterodactyle 
ilium  is  usually  that  of  the  embryo  bird,  and  its 
slender  processes  compare  in  relative  length  better 
with  those  of  the  unhatched  fowl  and  Apteryx  of 


96  DRAGONS    OF   THE   AIR 

New  Zealand  than  with  the  plate-like  form  in  adult 
birds. 

In  mammals  the  ilium  is  directed  forward,  and 
even  in  the  Cape  ant-eater  Orycteropus  there  is  only 
an  inappreciable  production  of  the  bone  backward 
behind  the  acetabulum.  Among  reptiles  the  general 
position  of  the  acetabulum  is  at  the  forward  termina- 
tion of  the  ilium,  though  the  Crocodile  has  some 
extension  of  the  bone  in  both  directions,  without 
forming  distinct  anterior  and  posterior  processes. 
This  anterior  and  posterior  extension  of  the  ilium 
is  seen  in  the  Theriodont  reptiles  of  Russia  and  of 
South  Africa,  as  well  as  in  Dinosaurs. 

Thirdly,  in  all  pterodactyles  the  ischium  and  pubis 
are  more  or  less  completely  blended  into  a  sheet  of 


FIG.  30.      LEFT  PELVIC  BONES  WITH   PREPUBIC  BONE   IN 
PTERODACTYLUS  LONGIROSTRIS 


bone,  unbroken  by  perforation,  though  there  is  usually 
a  minute  vascular  foramen  ;  or  the  lower  border  may 
be  notched  between  the  ischium  and  the  pubis,  as 
in  some  of  the  Solenhofen  species,  and  the  pubis 
does  not  reach  the  median  line  of  the  body.  But 
in  Dimorphodon  the  pelvic  sheet  of  bone  is  unbroken 
by  any  notch  or  perforation.  The  notch  between 
the  ischium  and  pubis  is  well  marked  in  Pterodactylus 
longirostris,  and  better  marked  in  Pterodactylus  dubius, 
Cycnorhamphus  Fraasii>  and  Rhamphorhynchus.  The 
fossil  animals  which  appear  to  come  nearest  to  the 
Pterodactyles  in  the  structure  of  the  pelvis  are 


THE   HIP-GIRDLE  AND    HIND   LIMB     97 

Theriodonts  from  the  Permian  rocks  of  Russia.  The 
type  known  as  Rhopalodon  has  the  ilium  less  pro- 
longed front  and  back,  and  is  much  deeper  than  in  any 
Pterodactyle  ;  but  the  acetabulum  is  imperforate,  and 
the  ischium  and  pubis  are  not  always  completely 
separated  from  each  other  by  suture.  In  the  pelvis 
referred  to  the  Theriodont  Deuterosaurus  there  is 
some  approximation  to  the  pelvis  of  Rhampho- 
rhynchus  and  of  Pterodactylus  d^lbius  in  the  depth 
of  the  division  between  the  pubis  and  ischium. 

There  are  three  modifications  of  the  Ornitho- 
saurian  pelvis.  First,  the  type  of  Rhamphorhynchus, 
in  which  the  pubis  and  ischium  are  inclined  some- 


FIG.  31 

PELVIS  AND  PREPUBIC   BONES  OF  RHAMPHORHYXCHUS 

On  the  left-hand  side  the  two  prepubic  bones  are  separate.     On 

the  right-hand  they  are  united  into  a  transverse  bar  which 

overlaps  the  front  of  pelvis  seen  from  the  under  side 

what  backward,  and  in  which  the  two  prepubic  bones 
are  triangular,  and  are  often  united  together  to  form 
a  transverse  bow  in  front  of  the  pubic  region. 

Secondly,  there  is  the  ordinary  form  of  pelvis  in 
which  the  pubis  and  ischium  usually  unite  with  each 
other  down  their  length,  as  in  Dimorphodon,  but 
sometimes,  as  in  Pterodactylus  dubius,  divide  im- 
mediately below  the  acetabulum.  All  these  types 
possess  the  paddle-shaped  prepubic  bones,  which  are 
never  united  in  the  median  line. 

Thirdly,  there  is  the  cretaceous  form  indicated  by 


98  DRAGONS   OF   THE   AIR 

Ornithocheirus  and  Ornithostoma,  in  which  the 
posterior  half  of  the  ilium  is  modified  in  a  singular 
way,  since  it  is  more  elevated  towards  the  sacrum 
than  the  anterior  half,  suggesting  the  contour  of  the 
upper  border  of  the  ilium  in  a  lizard.  Without  being 
reptilian  —  the  anterior  prolongation  of  the  bone 
makes  that  impossible — it  suggests  the  lizards.  This 
type  also  possesses  prepubic  bones.  They  appear, 
according  to  Professor  Williston,  to  be  more  like 
the  paddle-shaped  bones  of  Pterodactylus  than  like 
the  angular  bones  in  Rhamphorhynchus.  The  pre- 
pubic bones  are  united  in  the  median  line  as  in 


Prepubic  bones 


FIG.  32.      THE   PELVIC   BONES   OF   AN   ALLIGATOR 

SEEN    FROM    BELOW 

The  bones  in  front  are  here  regarded  as  prepubic,  but  are  commonly 
named  pubic 

Rhamphorhynchus.  But  their  median  union  in  that 
genus  favours  the  conclusion  that  the  bones  were 
united  in  the  median  line  in  all  species,  though  they 
are  only  co-ossified  in  these  two  families. 

This  median  union  of  the  prepubic  bones  is  a 
difference  from  those  mammals  like  the  Ornitho- 
rhynchus  and  Echidna,  which  approach  nearest  to 
the  Reptilia.  In  them  the  prepubic  bones  have  a  long 


THE   HIP-GIRDLE  AND    HIND   LIMB     99 

attachment  to  the  front  margin  of  the  pubis,  and 
extend  their  points  forward  without  any  tendency 
for  the  anterior  extremities  to  approximate  or  unite. 
The  marsupial  mammals  have  the  same  character, 
keeping  the  marsupial  bones  completely  distinct 
from  each  other  at  their  free  extremities.  The 
only  existing  animals  in  which  an  approximation 
is  found  to  the  prepubic  bones  in  Pterodactyles 
are  Crocodiles,  in  bones  which  most  writers  term  the 
pubic  bones.  This  resemblance,  without  showing 
any  strong  affinity  with  the  Crocodilia,  indicates 
that  Crocodiles  have  more  in  common  with  the 
fossil  flying  animals  than  any  other  group  of  existing 
reptiles;  for  other  reptiles  all  want  prepubic  bones, 
or  bones  in  front  of  the  pubic  region. 

THE   HIND   LIMB 

The  hind  limb  is  exceptionally  long  in  proportion 
to  the  back.  This  is  conspicuous  in  the  skeletons  of 
the  short-tailed  Pterodactyles,  and  is  also  seen  in 
Dimorphodon.  In  Rhamphorhynchus  the  hind  limb 
is  relatively  much  shorter,  so  that  the  animal,  when 
on  all  fours,  may  have  had  an  appearance  not  unlike 
a  Bat  in  similar  position.  The  limb  is  exception- 
ally short  in  the  little  Ptenodracon  brevirostris.  The 
bones  of  the  hind  limb  are  exceptionally  interesting. 
One  remarkable  feature  common  to  all  the  specimens 
is  the  great  elongation  of  the  shin  bones  relatively  to 
the  thigh  bones.  The  femur  is  sometimes  little  more 
than  half  the  length  of  the  tibia,  and  always  shorter 
than  that  bone.  The  proportions  are  those  of 
mammals  and  birds.  Some  mammals  have  the  leg 
shorter  than  the  thigh,  but  mammals  and  birds 
alone,  among  existing  animals,  have  the  proportions 


100 


DRAGONS   OF   THE   AIR 


which  characterise  Pterodactyles.  The  foot  appears 
to  have  been  applied  to  the  ground  not  always  as  in 
a  bird,  but  more  often  in  the  manner  of  reptiles,  or 
mammals  in  which  the  digits  terminate  in  claws. 

THE   FEMUR 

The  thigh  bone,  on  account  of  the  small  size  of 
many  of  the  specimens,  is  not  always  quite  clear 
evidence  as  an  indication  of  technical  resemblance  to 
other  animals.  The  bone  is  always  a  little  curved, 
has  always  a  rounded,  articular  head,  and  rounded 
distal  condyles.  Its  most  remarkable  features  are 


FIG.  33.      THE   FEMUR 

On  the  right  is  a  front  view  of  femur  of  a  bear.     In  the  middle  are  front  and 

side  views  of  the  femur  of  Ornithocheirus.     On  the  left  is  the  femur 

of  Echidna.     These  comparisons  illustrate  the  mammalian 

characters  of  the  Pterodactyle  thigh  bone 

shown  in  the  large,  well-preserved  specimens  from 
the  Cambridge  Greensand.  The  rounded,  articular 
head  is  associated  with  a  constricted  neck  to  the 
bone,  followed  by  a  comparatively  straight  shaft  with 
distal  condyles,  less  thickened  than  in  mammals.  No 
bird  is  known,  much  less  any  reptile,  with  a  femur 
like  Ornithocheirus.  Only  among  Mammals  is  a 
similar  bone  known  with  a  distinct  neck ;  and  only 
a  few  mammals  have  the  exceptional  characters  of 


THE   HIP-GIRDLE  AND    HIND   LIMB    101 

the  rounded  head  and  constricted  neck  at  all 
similar  to  the  Cretaceous  Pterodactyles.  A  few 
types,  such  as  the  higher  apes,  the  Hyrax,  and 
animals  especially  active  in  the  hind  limb,  have  a 
femur  at  all  resembling  the  Pterodactyle  in  the  pit 
for  the  obturator  externus  muscle,  behind  the  tro- 
chanter  major,  such  as  is  seen  in  a  small  femur  from 
Ashwell.  The  femur  varies  in  different  genera,  so  as 
to  suggest  a  number  of  mammalia  rather  than  any 
particular  animal  for  comparison.  These  approxi- 
mations may  be  consequences  of  the  ways  in  which 
the  bones  are  used.  When  functional  modifications 
of  the  skeleton  are  developed,  so  as  to  produce 
similar  forms  of  bones,  the  muscles  to  which  they 
give  attachment,  which  act  upon  the  bones,  and 
determine  their  growth,  are  substantially  the  same. 
In  the  Pterodactylus  longirostris  the  femur  corre- 
sponds in  length  to  about  eleven  dorsal  vertebrae. 
The  end  next  the  shin  bone  is  less  expanded  than 
is  usual  among  Mammals,  and  rather  suggests  an 
approach  to  the  condition  in  Crocodiles,  in  the  mode- 
rate thickness  and  breadth  of  the  articular  end,  and 
the  slight  development  of  the  terminal  pulley-joint. 
One  striking  feature  of  the  femur  is  the  circumstance 
that  the  articular  head,  as  compared  with  the  distal 
end,  is  directed  forward  and  very  slightly  inward  and 
upward.  So  that  allowing  for  the  outward  divergence 
of  the  pelvic  bones,  as  they  extend  forward,  there 
must  have  been  a  tendency  to  a  knock-kneed  ap- 
proximation of  the  lower  ends  of  the  thigh  bones, 
as  in  Mammals  and  Birds,  rather  than  the  outward 
divergence  seen  in  Reptiles. 

Apparently  the  swing  of  the  leg  and  foot,  as  it 
hung   on    the   distal  end  of   the    femur,  must  have 


102 


DRAGONS   OF  THE  AIR 


tended  rather  to  an  inward  than  to  an  outward 
direction,  so  that  the  feet  might  be  put  down  upon 
the  same  straight  line  ;  this  arrangement  suggests 
rapid  movement. 

TIBIA  AND   FIBULA 

In  Pterodactylus  longirostris  the  tibia  is  slender, 
more  than  a  fifth  longer  than  the  femur.  A  crest  is 
never  developed  at  the  proximal  end,  like  that  seen 

Tibia  Tibia 

»/  /I   FibU'a 
Fibula  ^ 


Dimorphodon 


Sarcorhamphus 


FIG.  34.      COMPARISON   OF  THE  TIBIA  AND   FIBULA 
IN   ORNITHOSAUR   AND  VULTURE 

in  the  Guillemot  and  Diver  and  other  water  birds. 
The  bone  is  of  comparatively  uniform  thickness  down 
the  shaft  in  most  of  the  Solenhofen  specimens,  as  in 
most  birds.  At  the  distal  end  the  shin  bone  com- 
monly has  a  rounded,  articular  termination,  like  that 
seen  in  birds.  This  is  conspicuous  in  the  Pterodac- 
tylus grandis.  In  other  specimens  the  tarsal  bones, 
which  form  this  pulley,  remain  distinct  from  the  tibia; 
and  the  upper  row  of  these  bones  appears  to  consist 


THE   HIP-GIRDLE  AND    HIND    LIMB    103 

of  two  bones,  like  those  which  in  many  Dinosaurs 
combine  to  form  the  pulley-like  end  of  the  tibia 
which  represents  the  bird's  drum-stick  bone.  They 
correspond  with  the  ankle  bones  in  man  named 
astragalus  and  os  calcis. 

Complete  English  specimens  of  tibia  and  fibula  are 
found  in  the  genus  Dimorphodon  from  the  Lias,  in 
which  the  terminal  pulley  of  the  distal  end  has  some 
expansion,  and  is  placed  forward  towards  the  front  of 
the  tibia,  as  in  some  birds.  The  rounded  surface  of 
the  pulley  is  rather  better  marked  than  in  birds. 
The  proximal  end  of  the  shaft  is  relatively  stout,  and 
is  modified  by  the  well-developed  fibula,  which  is  a 
short  external  splint  bone  limited  to  the  upper  half 
of  the  tibia,  as  in  birds ;  but  contributing  with  it  to 
form  the  articular  surface  for  the  support  of  the 
lower  end  of  the  femur,  taking  a  larger  share  in  that 
work  than  in  birds.  Frequently  there  is  no  trace  of 
the  fibula  visible  in  Solenhofen  specimens  as  pre- 
served ;  or  it  is  extremely  slender  and  bird-like,  as  in 
Pterodactylus  longirostris.  In  Rhamphorhynchus  it 
appears  to  extend  the  entire  length  of  the  tibia,  as  in 
Dinosaurs.  In  the  specimens  from  the  Cambridge 
Greensand  there  is  indication  of  a  small  proximal  crest 
to  the  tibia  with  a  slight  ridge,  but  no  evidence  that 
this  is  due  to  a  separate  ossification.  The  patella,  or 
knee-cap,  is  not  recognised  in  any  fossil  of  the  group. 
There  is  no  indication  of  a  fibula  in  the  specimens 
thus  far  known  from  the  Chalk  rocks  either  of  Kansas 
in  America,  or  in  England. 

The  region  of  the  tarsus  varies  from  the  circum- 
stance that  in  many  specimens  the  tibia  terminates 
downward  in  a  rounded  pulley,  like  the  drum-stick  of 
a  bird  ;  while  in  other  specimens  this  union  of  the 


104 


DRAGONS   OF  THE   AIR 


proximal  row  of  the  tarsal  bones  with  the  tibia  does 
not  take  place,  and  then  there  are  two  rows  of 
separate  tarsal  bones,  usually  with  two  bones  in  each 
row.  When  the  upper  row  is  united  with  the  tibia 
the  lower  row  remains  distinct  from  the  metatarsus, 
though  no  one  has  examined  these  separate  tarsal 
bones  so  as  to  define  them. 

THE   FOOT 

The  foot  sometimes  has  four  toes,  and  sometimes 
five.  There  are  four  somewhat  elongated,  slender 
metatarsal  bones,  which  are  separate  from  each  other 
and  never  blended  together,  as  in  birds.  There  has 


Pterodactylus 
FIG.  35. 


Rhaniphorhynchu 


METATARSUS  AND   DIGITS   IN   THREE  TYl'ES 
OF   ORNITHOSAURS 


been  a  suspicion  that  the  metatarsal  bones  were 
separate  in  the  young  Archaeopteryx.  In  the  young 
of  many  birds  the  row  of  tarsal  bones  at  the  proximal 
end  of  the  metatarsus  comes  away,  and  there  is  a 
partial  division  between  the  metatarsal  bones,  though 
they  remain  united  in  the  middle.  And  among  Pen- 
guins, in  which  the  foot  bones  are  applied  to  the 
ground  instead  of  being  carried  in  the  erect  position 
of  ordinary  birds,  there  is  always  a  partial  separation 


THE   HIP-GIRDLE  AND    HIND   LIMB    105 

between  the  metatarsal  bones,  though  they  become 
blended  together.  The  Pterodactyle  is  therefore 
different  from  birds  in  preserving  the  bones  distinct 
through  life,  and  this  character  is  more  like  Rep- 
tiles than  Mammals.  The  individual  bones  are  not 
like  those  of  Dinosaurs,  and  diverge  in  Rhampho- 
rhynchus  as  though  the  animals  were  web-footed. 
There  is  commonly  a  rudimentary  fifth  metatarsal. 
It  is  sometimes  only  a  claw-shaped  appendage,  like 
that  seen  in  the  Crocodile.  It  is  sometimes  a  short 
bone,  completely  formed,  and  carrying  two  phalanges 
in  Solenhofen  specimens :  though  no  trace  of  these 
phalanges  is  seen  in  the  large  toothless  Pterodactyles 
from  the  Cretaceous  rocks  of  North  America.  In  the 
Pterodactylus  longirostris  the  number  of  foot  bones 
on  the  ordinary  digits  is  two,  three,  four,  five,  as  in 
lizards ;  but  the  short  fifth  metatarsal  has  only  two 
toe  bones.  In  Dimorphodon  the  fifth  digit  was  bent 
upward,  and  supported  a  membrane  for  flight.  There 
are  slight  variations  in  the  number  of  foot  bones. 
In  the  species  Pterodactylus  scolopadceps  the  number 
of  bones  in  the  toes  follows  the  formula  two,  three, 
three,  four.  In  Pterodactylus  micronyx  the  number  is 
two,  three,  three,  three.  The  terminal  claws  are  much 
less  developed  than  is  usual  with  Birds ;  and  there  is 
a  difference  from  Bats  in  the  unequal  length  of  the 
digits.  Taken  as  a  whole,  the  foot  is  perhaps  more 
reptilian  than  avian,  and  in  some  genera  is  croco- 
dilian. 

The  foot  is  the  light  foot  of  an  active  animal.  Von 
Meyer  thought  that  the  hind  legs  were  too  slender 
to  enable  the  animal  to  walk  on  land  ;  and  Professor 
Williston,  of  the  University  of  Kansas,  remarks  that 
the  rudimentary  claws  and  weak  toes  indicate  that 


io6  DRAGONS   OF  THE  AIR 

the  animal  could  not  have  used  the  feet  effectively 
for  grasping,  while  the  exceedingly  free  movement 
of  the  femur  indicates  great  freedom  of  movement  of 
the  hind  legs  ;  and  he  concludes  that  the  function 
of  the  legs  was  chiefly  for  guidance  in  flight  through 
their  control  over  the  movements,  and  expresses  his 
belief  that  the  animal  could  not  have  stood  upon  the 
ground  with  its  feet.  There  may  be  evidence  to 
sustain  other  views.  If  the  limb  bones  are  recon- 
structed, they  form  limbs  not  wanting  in  elegance 
or  length.  If  it  is  true,  as  Professor  Williston  sug- 
gests, that  the  weight  of  his  largest  animals  with  the 
head  three  feet  long,  and  a  stretch  of  wing  of  eighteen 
or  nineteen  feet,  did  not  exceed  twenty  pounds,  there 
can  be  no  objection  to  regarding  these  animals  as 
quadrupeds,  or  even  as  bipeds,  on  the  ground  of  the 
limbs  lacking  the  strength  necessary  to  support  the 
body.  The  slender  toes  of  many  birds,  and  even  the 
two  toes  of  the  ostrich,  may  be  thought  to  give  less 
adequate  support  for  those  animals  than  the  meta- 
tarsals  and  digits  of  Pterodactyles. 


CHAPTER   XI 

SHOULDER-GIRDLE   AND 
FORE    LIMB 

STERNUM 

THE  sternum  is  always  a  distinguishing  part  of 
the  bony  structure  of  the  breast.  In  Crocodiles 
it  is  a  cartilage  to  which  the  sternal  ribs  unite ;  and 
upon  its  front  portion  a  flat  knife-like  bone  called 
the  interclavicle  is  placed.  In  lizards  like  the  Chame- 
leon, it  is  a  lozenge-shaped  structure  of  thin  bony 
texture,  also  bearing  a  long  interclavicle,  which  sup- 
ports the  clavicular  bones,  named  collar  bones  in 
man,  which  extend  outward  to  the  shoulder  blades. 
Among  mammals  the  sternum  is  usually  narrow  and 
flat,  and  often  consists  of  many  successive  pieces  in 
the  middle  line,  on  the  under  side  of  the  body. 
Among  Bats  the  anterior  part  is  somewhat  widened 
from  side  to  side,  to  give  attachment  to  the  collar 
bones,  but  the  sternum  still  remains  a  narrow  bone, 
much  narrower  than  in  Dolphins,  and  not  differing 
in  character  from  many  other  Mammals,  notwith- 
standing the  Bat's  power  of  flight.  The  bone  de- 
velops a  median  keel  for  the  attachment  of  the 
muscles  of  the  breast,  but  something  similar  is  seen 
in  burrowing  Insectivorous  mammals  like  the  Moles. 
107 


io8  DRAGONS   OF   THE   AIR 

So  that,  as  Von  Meyer  remarked,  the  presence  of  a 
keel  on  the  sternum  is  not  in  itself  sufficient  evidence 
to  prove  flight. 

Among  birds  the  sternum  is  greatly  developed. 
Broad  and  short  in  the  Ostrich  tribe,  it  is  devoid  of 
a  keel  ;  and  therefore  the  keel,  if  present  in  a  bird, 
is  suggestive  of  flight.  The  keel  is  differently  de- 
veloped according  to  the  mode  of  attachment  of  the 
several  pectoral  muscles  which  cover  a  bird's  breast. 
In  several  water  birds  the  keel  is  strongly  developed 
in  front,  and  dies  away  towards  the  hinder  part  of 
the  sternum,  as  in  the  Cormorant  and  its  allies.  The 
sternum  in  German  Pterodactyles  is  most  nearly 
comparable  to  these  birds. 

In  the  Solenhofen  Slate  the  sternum  is  fairly  well 
preserved  in  many  Ornithosaurs.  It  is  relatively 


Front  Side  Front 

Rhamphorhynchus  Cormorant 

FIG.  36.      COMPARISON   OF  THE  STERNUM 

shorter  than  in  birds,  and  is  broader  than  long ;  but 
not  very  like  the  sternum  of  reptile  or  mammal  in 
form.  The  keel  is  limited  to  the  anterior  part  of  the 
shield  of  the  sternum,  as  in  Merganser  and  the  Cormo- 
rant, and  is  prolonged  forward  for  some  distance  in 
advance  of  it.  Von  Meyer  noticed  the  resemblance  of 
this  anterior  process  to  the  interclavicle  of  the  Croco- 


SHOULDER-GIRDLE  AND  FORE  LIMB    109 

dile  in  position ;  but  it  is  more  like  the  keel  of  a  bird's 
sternum,  and  is  not  a  separate  bone  as  in  Reptiles. 
In  Pterodactyles  from  the  Cretaceous  rocks,  the  side 
bones,  called  coracoids,  are  articulated  to  saddle- 
shaped  surfaces  at  the  hinder  part  of  the  base  of 
this  keel,  which  are  parallel  in  Ornithocheirus,  as  in 
most  birds,  but  overlap  in  Ornithodesmus,  as  in 
Herons  and  wading  birds. 

The  keel  was  pneumatic,  and  when  broken  is  seen 
to  be  hollow,  and  appears  to  have  been  exceptionally 


Front 


}id  articulation 


FIG.  37.      STERNUM   IN   ORNITHOCHEIRUS   FROM   THE 
CAMBRIDGE  GREENSAND 

Showing  the  strong  keel  and  the  facets  for  the  coracoid  bones  on  its  hinder 
border  above  the  lateral  constrictions 


high   in    Rhamphorhynchus,   a   genus  in  which  the 
wing  bones  are  greatly  elongated.    Von  Meyer  found 


no  DRAGONS   OF   THE   AIR 

in  Rhamphorhynchus  on  each  side  of  the  sternum  a 
separate  lateral  plate  with  six  pairs  of  sternal  ribs, 
which  unite  the  sternum  with  the  dorsal  ribs,  as  in 
the  young  of  some  birds.  The  hinder  surface  of  the 
sternum  is  imperfectly  preserved  in  the  toothless 
Pterodactyles  of  Kansas.  Professor  Williston  states 
that  the  bone  is  extremely  thin  and  pentagonal  in 
outline,  projecting  in  front  of  the  coracoids,  in  a 
stout,  blunt,  keel-like  process,  similar  to  that  seen  in 
the  Pterodactyles  of  the  Cambridge  Greensand. 
American  specimens  have  not  the  same  notch  be- 
hind the  articulation  for  the  coracoid  to  separate  it 
from  the  transverse  lateral  expansion  of  the  sternal 
shield.  The  lateral  margin  in  the  Cambridge  Green- 
sand  specimens  figured  by  Professor  Owen  and  my- 
self is  broken  ;  but  Professor  Williston  had  the  good 
fortune  to  find  on  the  margin  of  the  sternum  the 
articular  surfaces  which  gave  attachment  to  the  sternal 
ribs.  The  margin  of  the  sternal  bone  thickens  at  these 
facets,  four  of  which  are  preserved.  The  sternum  in 
Ornithostoma  was  about  four  and  a  half  inches  long 
by  less  than  five  and  a  half  inches  wide.  The  median 
keel  extends  forward  for  rather  less  than  two  inches, 
while  in  the  smaller  Cambridge  species  of  Ornitho- 
cheirus  it  extends  forward  for  less  than  an  inch  and 
a  half. 

A  sternum  of  this  kind  is  unlike  that  of  any  other 
animal,  but  has  most  in  common  with  a  bird ;  and 
may  be  regarded  as  indicating  considerable  power 
of  flight.  The  bone  cannot  be  entirely  attributed  to 
the  effect  of  flight,  since  there  is  no  such  expanded 
sternal  shield  in  Bats.  The  small  number  of  sternal 
ribs  is  even  more  characteristic  of  birds  than  mam- 
mals or  reptiles. 


SHOULDER-GIRDLE  AND  FORE  LIMB    in 


THE   SHOULDER-GIRDLE 

The  bones  which  support  the  fore  limb  are  one 
of  the  distinctive  regions  of  the  skeleton  defining 
the  animal's  place  in  nature.  Among  most  of  the 
lower  vertebrata,  such  as  Amphibians  and  Rep- 
tiles, the  girdle  is  a  double  arch — the  arch  of  the 
collar  bone  or  clavicles  in  front,  and  the  arch  of  the 
shoulder-blade  or  scapula  behind.  The  clavicular 
arch,  when  it  exists,  is  formed  of  three  or  five  parts — 
a  medium  bar  named  the  interclavicle,  external  to 
which  is  a  pair  of  bones  called  clavicles,  reaching  to 
the  front  of  the  scapulae  when  they  are  present ;  and 
occasionally  there  is  a  second  pair  of  bones  called 
supraclavicles,  extending  from  the  clavicles  up  the 
front  margins  of  the  scapulae.  Thus  the  clavicular 
arch  is  placed  in  front  of  the  scapular  arch.  The 
supraclavicles  are  absent  from  all  living  Reptiles,  and 
the  clavicles  are  absent  from  Crocodiles.  The  inter- 
clavicle  is  absent  from  all  mammals  except  Echidna 
and  Ornithorhynchus.  Clavicles  also  may  be  absent 
in  some  orders  of  mammals.  Hence  the  clavicular 
arch  may  be  lost,  though  the  collar  bones  are  re- 
tained in  man. 

The  scapular  arch  also  is  more  complicated  and 
more  important  in  the  lower  than  in  the  higher 
vertebrata.  It  may  include  three  bones  on  each  side 
named  coracoid,  precoracoid,  and  scapula.  But  in 
most  vertebrates  the  coracoid  and  precoracoid  appear 
never  to  have  been  segmented  so  as  to  be  separated 
from  each  other ;  and  it  is  only  among  extinct  types 
of  reptiles,  which  appear  to  approximate  to  the  Mono- 
treme  mammals,  that  separate  precoracoid  bones  are 
found ;  though  among  most  mammals,  probably, 


ii2  DRAGONS   OF  THE   AIR 

there  are  stages  of  early  development  in  which  pre- 
coracoids  are  represented  by  small  cartilages,  though 
few  mammals  except  Edentata  like  the  Sloths  and 
Ant-eaters,  retain  even  the  coracoids  as  distinct  bones. 
Therefore,  excepting  the  Edentata  and  the  Mono- 
tremes,  the  distinctive  feature  of  the  mammalian 
shoulder-girdle  appears  to  be  that  the  limbs  are  sup- 
ported by  the  shoulder-blades,  termed  the  scapulae. 

Among  reptiles  there  are  several  distinct  types 
of  shoulder-girdle.  Chelonians  possess  a  pair  of 
bones  termed  coracoids  which  have  no  connexion 
with  a  sternum  ;  and  their  scapulae  are  formed  of  two 
widely  divergent  bars,  divided  by  a  deeper  notch  than 
is  found  in  any  fossil  reptiles.  Among  Lizards  both 
scapula  and  coracoid  are  widely  expanded,  and  the 
coracoid  is  always  attached  to  the  sternum.  Chame- 
leons have  the  blade  of  the  scapula  long  and  slender, 
but  the  coracoid  is  always  as  broad  as  it  is  long. 
Crocodiles  have  the  bone  more  elongated,  so  that  it 
has  somewhat  the  aspect  of  a  very  strong  first  sternal 
rib  when  seen  on  the  ventral  face  of  the  animal.  The 
bone  is  perforated  by  a  foramen,  which  would  prob- 
ably lie  in  the  line  of  separation  from  the  precoracoid 
if  any  such  separation  had  ever  taken  place.  The 
scapula,  or  shoulder-blade,  of  Crocodiles  is  a  similar 
flat  bone,  very  much  shorter  than  the  scapula  of  a 
Chameleon,  and  more  like  that  of  the  New  Zealand 
Hatteria.  Thus  there  is  very  little  in  common  be- 
tween the  several  reptilian  types  of  shoulder-girdle. 

In  birds  the  apparatus  for  the  support  of  the  wings 
has  a  far-off  resemblance  to  the  Crocodilian  type. 
The  coracoid  bones,  instead  of  being  directed  laterally 
outward  and  upward  from  the  sternum,  as  among 
Crocodiles,  are  directed  forward,  so  as  to  prolong  the 


SHOULDER-GIRDLE  AND  FORE  LIMB    113 


line  of  the  breast  bone,  named  the  sternum.  The 
bird's  coracoid  is  sometimes  flattened  towards  the 
breast  bone  among  Swans  and  other  birds ;  yet  as  a 
rule  the  coracoid  is  a  slender  bar,  which  combines 
with  the  still  more  slender  and  delicate  blade  of  the 
scapula,  which  rests  on  the  ribs,  to  make  the  articula- 
tion for  the  upper  arm  bone.  Among  reptiles  the 
scapula  and  coracoid  are  more  or  less  in  the  same 


Articulation  for  the 
Dimorphodon         humerus 
Lias 


Rhamphocephalus 

Stonesfield  Slate 


Scapula 


Scapula 


Pterodactyle 
|        Oxford  Clay 

Coracoid  Coi 

Articulation  with  the  sternum 


coid 


Aramis  (bird) 


FIG.   38.      COMPARISON   OF   SCAPULA   AND   CORACOID   IN 
THREE   PTERODACTYLES   AND   A   BIRD 

straight  line,  as  in  the  Ostrich,  but  in  birds  of  flight 
they  meet  at  an  angle  which  is  less  than  a  right  angle, 
and  where  they  come  in  contact  the  external  surface 
is  thickened  and  excavated  to  make  the  articulation 
for  the  head  of  the  humerus.  There  is  nothing  like 
this  shoulder-girdle  outside  the  class  of  birds,  until  it 
is  compared  with  the  corresponding  structure  in  these 


ii4  DRAGONS    OF   THE   AIR 

extinct  animals  called  Pterodactyles.  The  resem- 
blance between  the  two  is  surprising.  It  is  not 
merely  the  identity  of  form  in  the  coracoid  bone  and 
the  scapula,  but  the  similar  angle  at  which  they  meet 
and  the  similar  position  of  the  articulation  for  the 
humerus.  Everything  in  the  Pterodactyle's  shoulder- 
girdle  is  bird-like,  except  the  absence  of  the  repre- 
sentative of  the  clavicles,  that  forked  V-shaped  bone 
of  the  bird  which  in  scientific  language  is  known  as 
the  furculum,  and  is  popularly  termed  the  "  merry- 
thought." This  kind  of  shoulder-girdle  is  found  in 
the  genera  from  the  Lias  and  the  Oolitic  rocks,  both 
of  this  country  and  Germany. 

In  the  Cretaceous  rocks  the  scapula  presents,  in 
most  cases,  a  different  appearance.  The  coracoid  is 
an  elongated,  somewhat  triangular  bone,  compressed 
on  the  outer  margin  as  in  birds,  but  differing  alike 
from  birds  and  other  Pterodactyles  in  not  being 
prolonged  forward  beyond  the  articulation  for  the 
humerus.  In  these  Cretaceous  genera,  toothed  and 
toothless  alike,  the  articulation  for  the  upper  arm 
bone  truncates  the  extremity  of  the  coracoid,  so  that 
the  bone  is  less  like  that  of  a  bird  in  this  feature. 
Perhaps  it  shows  a  modification  towards  the  croco- 
dilian direction.  The  scapula,  which  unites  with  the 
coracoid  at  about  a  right  angle,  is  similarly  truncated 
by  the  articular  surface  for  the  humerus ;  but  the 
bone  is  somewhat  expanded  immediately  beyond  the 
articulation,  and  compressed  ;  and  instead  of  being 
directed  backward,  it  is  directed  inward  over  the  ribs 
to  articulate  with  the  neural  arches  of  the  early 
dorsal  vertebrae  in  the  genera  found  in  strata  asso- 
ciated with  the  Chalk.  As  the  bone  approaches 
this  articulation,  it  thickens  and  widens  a  little, 


SHOULDER-GIRDLE  AND  FORE  LIMB    115 

becoming    suddenly    truncated    by   an    ovate    facet, 
which  exactly  corresponds  to  the  transversely  ovate 


FIG.   39.      THE   NOTARIUM 

An  ossification  which  gives  attachment  to  the  scapulae  seen  in 

the  early  dorsal  vertebra  of  Ornithocheirus 

(From  the  Cambridge  Greensand) 

impression,  concave  from  front  to  back,  which  is  seen 
in  the  neural  arches  of  the  dorsal  vertebrae  on  which 
it  fits.  This  condition  is  not  present  in  all  Cretaceous 


Scapula 


FIG.  40.      RESTORATION   OF   THE   SHOULDER-GIRDLE   IN   THE 

CRETACEOUS  ORNITHOCHEIRUS 

Showing  how  the  scapulas  articulate  with  a  vertebra  and  the  articulation 
of  the  coracoids  with  the  sternum.     The  humeral  articulation  with 
the  coracoid  is  unlike  the  condition  shown  in  other  Ornithosaurs 

Pterodactyles.    It  does  not  occur  in  the  Kansas  fossil, 
named  by  Professor  Marsh,  Nyctodactylus.     And  it 


ii6  DRAGONS   OF  THE   AIR 

appears  to  be  absent  from  the  Pterodactyles  of  the 
English   Weald,  named  Ornithodesmus. 

There  is  no  approach  to  this  transverse  position  of 
the  scapulae  among  birds.  And  while  the  form  of 
the  bones  in  the  older  genera  of  Ornithosaurs  is 
singularly  bird-like,  the  angular  arrangement  in  this 
Cretaceous  genus  is  obtained  by  closely  approximat- 
ing the  articulations  on  the  sternum,  so  that  the 
coracoids  extend  outward  as  in  reptiles,  instead  of 
forward  as  in  birds ;  and  the  extremities  of  the 
scapula  similarly  approximate  towards  each  other. 
This  rather  recalls  the  relative  positions  of  scapula 
and  coracoid  among  crocodiles.  If  crocodile  and 
bird  had  been  primitive  types  of  animals  instead  of 
surviving  types,  it  might  almost  seem  as  though 
there  had  been  a  cunning  and  harmonious  blending 
of  one  with  the  other  in  evolving  this  form  of 
shoulder-girdle. 

THE   FORE   LIMB 

The  bones  of  the  fore  limb,  generally,  correspond 
in  length  with  the  similar  parts  of  the  hind  limb. 
The  upper  arm  bone  corresponds  with  the  upper  leg 
bone,  and  the  fore-arm  bone  is  as  long  as  the  fore- 
leg bone;  then  differences  begin.  The  bones  which 
correspond  to  the  back  of  the  hand  in  man,  termed 
the  metacarpus,  are  variable  in  length  in  Pterodactyles 
— sometimes  very  long  and  sometimes  short.  The 
wing  metacarpal  bone  is  always  stout,  and  the  others 
are  slender.  The  extremity  of  the  metacarpus  was 
applied  to  the  ground.  Three  small  digits  of  the 
hand  are  developed  from  the  three  small  metacarpal 
bones,  and  terminate  in  large  claws. 

The  great  wing  finger  was  bent  backward,  and  only 


SHOULDER-GIRDLE  AND  FORE  LIMB    117 

touched  the  ground  where  it  fitted  upon  the  wing 
metacarpal  bone.  It  appears  sometimes  to  have 
been  as  long  as  the  entire  vertebral  column. 

Owing  to  the  circumstance  that  the  joint  in  the 
arm  in  Pterodactyles  was  not  at  the  wrist  as  among 
birds,  but  between  the  metacarpus  and  the  phalanges, 
it  follows  that  the  fore  limb  was  longer  than  the  hind 
limb  when  the  metacarpus  was  long ;  but  the  differ- 
ence would  not  interfere  with  the  movements  of  the 
animal,  either  upon  four  feet  or  on  two  feet,  for  in  bats 
and  birds  the  disproportion  in  length  is  greater. 

HUMERUS  OR  UPPER  ARM  BONE 
The  first  bone  in  the  fore-arm,  the  humerus,  is 
remarkable  chiefly  for  the  compressed  crescent  form 
of  its  upper  articular  end,  which  is  never  rounded 
like  the  head  of  the  upper  arm  bone  in  man,  and 
secondly  for  the  great  development  of  the  external 
process  of  bone  near  that  end,  termed  the  radial 
crest.  Sir  Richard  Owen  compared  the  bone  to  the 
humerus  of  both  birds  and  crocodiles,  but  in  its  upper 
articular  end  the  crocodile  bone  may  be  said  to  be 
more  like  a  bird  than  it  is  like  the  Pterodactyle.  In 
flying  reptiles  the  articular  surface  next  the  shoulder- 
girdle  is  somewhat  saddle-shaped,  being  concave  from 
side  to  side  above  and  convex  vertically,  while  most 
animals  with  which  it  can  be  compared  have  the 
articular  head  of  the  bone  convex  in  both  directions. 
A  remarkable  exception  to  this  general  rule  is  found 
in  some  fossil  animals  from  South  Africa,  which,  from 
resemblance  to  mammals  in  their  teeth,  have  been 
termed  Theriodonts.  They  sometimes  have  the  head 
of  the  bone  concave  from  side  to  side  and  convex  in 
the  vertical  direction.  To  this  condition  Ornitho- 


n8  DRAGONS    OF   THE   AIR 

rhynchus  makes  a  slight  approximation.  The  singu- 
lar expansion  of  the  structure  called  the  radial  crest 
finds  no  close  parallel  in  reptiles,  though  Crocodiles 
have  a  moderate  crest  on  the  humerus  in  the  same 
position  ;  and  in  Theriodonts  the  radial  crest  extends 
much  further  down  the  shaft  of  the  humerus.  No 
bird  has  a  radial  crest  of  a  similar  kind,  though  it 
is  prolonged  some  way  down  the  shaft  in  Archaeop- 
teryx.  In  Pterodactyles  it  sometimes  terminates 
outward  in  a  smooth,  rounded  surface,  which  might 
have  been  articular  if  any  structure  could  have  articu- 
lated with  it.  There  is  also  a  moderate  expansion  of 
the  bone  on  the  ulnar  side  in  some  Pterodactyles,  so 
that  the  proximal  end  often  incloses  nearly  three- 
fourths  of  an  ovate  outline.  The  termination  of  the 
radial  crest  is  at  the  opposite  end  of  this  oval  to  the 
wider  articular  part  of  the  head  of  the  bone,  in 
some  specimens  from  the  Cambridge  Greensand.  The 
radial  crest  is  more  extended  in  Rhamphorhynchus. 
All  specimens  of  the  humerus  show  a  twist  in  the 
length  of  the  bone,  so  that  the  end  towards  the  fore- 
arm, which  is  wider  than  the  shaft,  makes  a  right 
angle  with  the  radial  crest  on  the  proximal  end, 
which  is  not  seen  in  birds.  The  shaft  of  the  hume- 
rus is  always  stouter  than  that  of  the  femur,  though 
different  genera  differ  in  this  respect. 

The  humerus  in  genera  from  rocks  associated  with 
the  Chalk  presents  two  modifications,  chiefly  seen  in 
the  characters  of  the  distal  end  of  the  bone.  One  of 
these  is  a  stout  bone  with  a  curiously  truncated  end 
where  it  joins  the  two  bones  of  the  fore-arm  ;  and 
the  other  is  more  or  less  remarkable  for  the  rounded 
form  of  the  distal  condyles.  Both  types  show  distinct 
articular  surfaces.  The  inner  one  is  somewhat  oblique 


SHOULDER-GIRDLE  AND  FORE  LIMB    119 

and  concave,  the  outer  one  rounded  ;  the  two  being 
separated  by  a  concave  channel,  so  that   the  ulna 


Ornithocheirus  Pigeon 

FIG.  41.      COMPARISON   OF  THE   HUMERUS   IN 
PTERODACTYLS  AND  BIRD 

makes  an  oblique  articulation  with  the  bone  as  in 
birds,  and  the  radius  articulates  by  a  more  or  less 
truncated  or  concave  surface. 

ULNA   AND   RADIUS 

The  bones  of  the  fore-arm  are  similar  to  each  other 
in  size,  and  if  there  be  any  difference  between  them 
the  ulna  is  slightly  the  larger.  There  is  some  evidence 
that  in  Rhamphorhynchus  the  upper  end  of  the  ulna 
was  placed  behind  the  radius,  probably  in  consequence 
of  the  mode  of  attachment  of  those  bones  to  the 
humerus.  The  ulna  abutted  towards  the  inner  and 
lower  border,  while  the  radius  was  towards  the  upper 
border,  consequent  upon  the  twist  in  the  humerus. 
This  condition  corresponds  substantially  with  the 
arrangement  in  birds,  but  differs  from  birds  in  the 
relatively  more  important  part  taken  by  the  radius 
in  making  the  articulation.  The  bones  are  compared 
in  Dimorphodon  with  the  Golden  Eagle  drawn  of  the 
same  size  (Fig.  42).  In  birds  the  ulna  supports  the  great 
feathers  of  the  wing,  and  this  may  account  for  the 


120 


DRAGONS   OF   THE   AIR 


size  of  the  bone.  The  ulna  is  best  seen  at  its  proxi- 
mal end  in  the  specimens  from  the  Cambridge 
Greensand,  where  there  is  a  terminal  olecranon  ossi- 
fication forming  an  oblique  articulation,  which  fre- 
quently comes  away  and  is  lost.  It  is  sometimes 
well  preserved,  and  indicated  by  a  suture.  The 
examples  of  ulna  from  the  Lias  show  a  slight  ex- 
pansion of  the  bone  at  both  ends,  and  at  the  distal 
end  toward  the  wrist  the  articulation  is  well  defined, 


Ulna    Radii 


Ulna      Radius 


fl 


Golden  Eagle  Dimorphodon 

FIG.  42.      COMPARISON  OF   THE  BONES  OF  THE   FORE-ARM 
IN   BIRD  AND  ORNITHOSAUR 


where  the  bone  joins  the  carpus.  The  larger  speci- 
mens of  the  bone  are  broken.  The  distal  articular 
surface  is  only  connected  with  the  proximal  end  of 
the  bone  in  small  specimens :  it  always  shows  on 
the  one  margin  a  concavity,  followed  by  a  prominent 
boss,  and  an  oblique  articulation  beyond  the  boss. 
On  the  side  towards  the  radius,  on  the  lower  end  of 
the  shaft  there  is  an  angular  ridge,  which  marks  the 


SHOULDER-GIRDLE  AND  FORE  LIMB    121 

line  along  which  the  ulna  overlaps  the  radius.  The 
lower  end  of  the  radius  has  a  simple,  slightly  convex 
articulation,  somewhat  bean-shaped.  No  rotation 
of  these  bones  on  each  other  was  possible  as  in 
man.  There  is  a  third  bone  in  the  fore-arm.  This 
bone,  named  the  pteroid,  is  commonly  seen  in  skele- 
tons from  Solenhofen.  It  was  regarded  by  Von 
Meyer  as  having  supported  the  wing  membrane  in 
flight.  Some  writers  have  interpreted  it  as  an  essen- 
tial part  of  the  Pterodactyle  skeleton,  and  Von 
Meyer  thought  that  it  might  possibly  indicate  a  fifth 
digit  in  the  hand.  The  only  existing  structure  at  all 
like  it  is  seen  in  the  South  African  insectivorous 
mammal  named  Chrysochloris  capensis,  the  golden 
mole,  which  also  has  three  bones  in  the  fore-arm, 
the  third  bone  extending  half-way  up  towards  the 
humerus.  In  that  animal  the  third  bone  appears  to 
be  behind  the  others  and  adjacent  to  the  ulna.  In 
the  German  fossils  the  pteroid  articulated  with  a 
separate  carpal  or  metacarpal  bone,  placed  on  the  side 
of  the  arm  adjacent  to  the  radius,  and  the  radius 
is  always  more  inward  than  the  ulna.  If  the  view 
suggested  by  Von  Meyer  is  adopted,  this  bone  would 
be  a  first  digit  extending  outward  and  backward 
towards  the  humerus.  That  view  was  adopted  by 
Professor  Marsh.  It  involves  the  interpretation  of 
what  has  been  termed  the  lateral  carpal  as  the  first 
metacarpal  bone,  which  would  be  as  short  as  that 
of  a  bird,  but  turned  in  the  opposite  direction  back- 
ward. The  first  digit  would  then  only  carry  one 
phalange,  and  would  not  terminate  in  a  claw,  but  lie 
in  the  line  of  the  tendon  which  supports  the  anterior 
wing  membrane  of  a  bird. 

The  third  bone  in  the  fore-arm  of  Chrysochloris 


122  DRAGONS   OF  THE   AIR 

does  not  appear  to  correspond  to  a  digit.  The  bone 
is  on  the  opposite  side  of  the  arm  to  the  similar 
bone  of  a  Pterodactyle,  and  therefore  cannot  be  the 
same  structure  in  the  Golden  Mole.  The  interpreta- 
tion which  makes  the  pteroid  bone  the  first  digit 
has  the  merit  of  accounting  for  the  fifth  digit  of  the 
hand.  All  the  structures  of  the  hand  are  consistent 
with  this  view.  The  circumstance  that  the  bone  is 
rarely  found  in  contact  with  the  radius,  but  diverging 
from  it,  shows  that  it  plays  the  same  part  in  stretching 
the  membrane  in  advance  of  the  arm,  that  the  fifth 
digit  holds  in  supporting  the  larger  wing  membrane 
behind  the  arm. 

According  to  Professor  Williston,  the  American 
toothless  Pterodactyle  Ornithostoma  has  but  a  single 
phalange  on  the  corresponding  first  toe  of  the  hind 
foot,  and  that  bone  he  describes  as  long,  cylindrical, 
gently  curved,  and  bluntly  pointed.  There  is  some 
support  for  this  interpretation ;  but  I  have  not  seen 
any  English  or  German  Pterodactyles  with  only  one 
phalange  in  the  first  toe. 

The  wing  in  Pterodactyles  would  thus  be  stretched 
between  two  fingers  which  are  bent  backward,  the 
three  intermediate  digits  terminating  in  claws. 

THE   CARPUS 

The  wrist  bones  in  the  reptilia  usually  consist  of 
two  rows.  In  Crocodiles,  in  the  upper  row  there  is 
a  large  inner  and  a  small  outer  bone,  behind  which 
is  a  lunate  bone,  the  remainder  of  the  carpus  being 
cartilaginous.  Only  one  carpal  is  converted  into 
bone  in  the  lower  row.  It  is  placed  immediately 
under  the  smaller  upper  carpal.  In  Chelonians,  the 
turtle  and  tortoise  group,  the  characters  of  the  carpus 


SHOULDER-GIRDLE  AND  FORE  LIMB    123 

vary  with  the  family.  In  the  upper  row  there  are 
usually  two  short  carpals,  which  may  be  blended, 
under  the  ulna ;  while  the  two  under  the  radius  are 
commonly  united.  The  lower  row  is  made  up  of 
several  small  bones.  Lizards,  too,  usually  have  three 
bones  in  the  proximal  row  and  five  smaller  bones 
in  the  distal  row. 

The  correspondence  of  the  distal  carpals  with 
the  several  metacarpal  bones  of  the  middle  hand 
is  a  well-known  feature  of  the  structure  of  the 
wrist. 

Von  Meyer  remarks  that  the  carpus  is  made  up  of 
two  rows  of  small  bones  in  the  Solenhofen  Ptero- 
dactyles  ;  while  in  birds  there  is  one  row  consisting 
of  two  bones.  The  structure  of  the  carpus  is  not 
distinct  in  all  German  specimens ;  but  in  the  short- 
tailed  Solenhofen  genera  the  bones  in  the  two  rows 
retain  their  individuality. 

In  all  the  Cretaceous  genera  the  carpal  bones  of 
each  row  are  blended  into  a  single  bone,  so  that  two 
bones  are  superimposed,  which  may  be  termed  the 
proximal  and  distal  carpals.  One  specimen  shows 
by  an  indication  of  sutures  the  original  division  of 
the  distal  carpal  into  three  bones  ;  and  the  separated 
constituent  bones  are  very  rarely  met  with.  Two 
bones  of  the  three  confluent  elements  contribute  to  the 
support  of  the  wing  metacarpal,  and  the  third  gives 
an  articular  attachment  to  the  bone  which  extends 
laterally  at  the  inner  side  of  the  carpus,  which  I 
now  think  may  be  the  first  metacarpal  bone  turned 
backward  towards  the  humerus.  The  three  com- 
ponent bones  meet  in  the  circular  pneumatic  fora- 
men in  the  middle  of  the  under  side  of  the  distal 
carpal.  There  is  no  indication  of  division  of  the 


i24  DRAGONS   OF  THE   AIR 

proximal    carpal    in   these   genera    into    constituent 
bones. 

This  condition  is  somewhat  different  from  birds. 
In    1873    Dr.    Rosenberg,   of   Dorpat,   showed    that 


Lateral 
(carpal  or)         I  .  XX  "\  (         Proximal  carpal 


Distal  carpal 

FIG.  43.      CARPUS   FROM   ORNITHOCHEIRUS 
(Cambridge  Greensand) 

there  is  in  the  bird  a  proximal  carpal  formed  of  two 
elements,  and  a  distal  carpal  also  formed  of  two 
elements.  Therefore  the  two  constituents  of  the 
distal  carpal  in  the  bird  which  blends  in  the  mature 
animal  with  the  metacarpus,  forming  the  rounded 
pulley  joint,  may  correspond  with  two  of  the  three 
bones  in  the  Cretaceous  Pterodactyle  Ornithocheirus. 

The  width  of  a  proximal  carpal  rarely  exceeds  two 
inches,  and  that  of  a  distal  carpal  is  about  an  inch 
and  three-quarters.  Two  such  bones  when  in  contact 
would  not  measure  more  than  one  inch  in  depth. 
The  lower  surface  shows  that  the  wing  had  some 
rotary  movement  upon  the  carpus  outward  and 
backward. 

METACARPUS 

The  metacarpus  consists  of  bones  which  corre- 
spond to  the  back  of  the  hand.  The  first  digit  of 
the  hand  in  clawed  animals  has  the  metacarpal  bone 
short,  or  shorter  than  the  others.  Among  mammals 
metacarpal  bones  are  sometimes  greatly  elongated  ; 
and  a  similar  condition  is  found  in  Pterodactyles,  in 
which  the  metacarpal  bone  may  be  much  longer 


SHOULDER-GIRDLE  AND  FORE  LIMB    125 

than  the  phalange  which  is  attached  to  it.  Two 
metacarpal  bones  appear  to  be  singularly  stouter 
than  the  others.  The  first  bone  of  the  first  digit,  if 
rightly  determined,  is  much  shorter  than  the  others, 
and  is,  in  fact,  no  longer  than  the  carpus  (Fig.  43).  It 
is  a  flat  oblong  bone,  attached  to  the  inner  side  of 
the  lower  carpal,  and  instead  of  being  prolonged 
distally  in  the  same  direction  as  the  other  meta- 
carpal bones,  is  turned  round  and  directed  upward, 
so  that  its  upper  edge  is  flush  with  the  base  of  the 
radius,  and  gives  attachment  to  a  bone  which  re- 
sembles a  terminal  phalange  of  the  wing  finger. 


FIG.  44.       METACARPUS   IN   TWO  ORNITHOSAURS 

According  to  this  interpretation  it  is  the  first  and 
only  phalange  in  the  first  digit.  The  bone  is  often 
about  half  as  long  as  the  fore-arm,  terminates  up- 
ward in  a  point,  is  sometimes  curved,  and  frequently 
diverges  outward  from  the  bones  of  the  fore-arm, 
as  preserved  in  the  associated  skeleton,  being 
stretched  towards  the  radial  crest  of  the  humerus. 
This  mode  of  attachment  of  the  supposed  first  meta- 
carpal, which  is  true  for  all  Cretaceous  pterodactyles, 
has  not  been  shown  to  be  the  same  for  all  those 
from  the  Solenhofen  Slate.  There  is  no  greater 
anomaly  in  this  metacarpal  and  phalange  on  the 


126  DRAGONS   OF   THE   AIR 

inner  side  being  bent  backward,  than  there  is  in  the 
wing  finger  being  bent  backward  on  the  outer  side. 
The  three  slender  intervening  digits  extend  forward 
between  them,  as  though  they  were  applied  to  the 
ground  for  walking. 

The  bone  which  is  usually  known  as  the  wing 
metacarpal  is  frequently  stouter  at  the  proximal  end 
towards  the  carpus  than  towards  the  phalange.  At 
the  carpal  end  it  is  oblong  and  truncated,  with  a  short 
middle  process,  which  may  have  extended  into  the 
pit  in  the  base  of  the  carpal  bone ;  while  the  distal 
terminal  end  is  rounded  exactly  like  a  pulley.  There 
is  great  difference  in  the  length  of  the  metacarpus. 
In  the  American  genus  Ornithostoma  it  is  much 
longer  than  the  fore-arm.  In  Rhamphorhynchus  it 
is  remarkably  short,  though  perhaps  scarcely  so 
short  as  in  Dimorphodon  or  in  Scaphognathus.  The 
largest  Cretaceous  examples  are  about  two  inches 
wide  where  they  join  the  carpus.  The  bone  is  some- 
times a  little  curved. 

Between  the  first  and  fifth  or  wing  metacarpal  are 
the  three  slender  metacarpal  bones  which  give  attach- 
ment to  the  clawed  digits.  They  bear  much  the 
same  relation  to  the  wing  metacarpal  that  the  large 
metatarsal  of  a  Kangaroo  has  to  the  slender  bones 
of  the  instep  which  are  parallel  to  it. 

The  facet  for  the  wing  metacarpal  on  the  carpus  is 
clearly  recognised,  but  as  a  rule  there  is  no  surface 
with  which  the  small  metacarpals  can  be  separately 
articulated.  One  or  two  exceptional  specimens  from 
the  Cambridge  Greensand  appear  to  have  not  only 
surfaces  for  the  wing  metacarpal,  but  two  much 
smaller  articular  surfaces,  giving  attachment  to 
smaller  metacarpals;  while  in  one  case  there  appears 


SHOULDER-GIRDLE  AND  FORE  LIMB    127 

to  be  only  one  of  these  additional  impressions.  It 
is  certain  that  all  the  animals  from  the  Lias  and 
Oolites  have  three  clawed  digits,  but  at  present  I 
have  seen  no  evidence  that  there  were  three  in  the 
Cretaceous  genera,  though  Professor  Williston's  state- 
ments and  restoration  appear  to  show  that  the 
toothless  Pterodactyles  have  three.  Another  differ- 
ence from  the  Oolitic  types,  according  to  Professor 
Williston,  is  in  the  length  of  the  slender  metacarpals 
of  the  clawed  phalanges  being  about  one-third  that 
of  the  wing  metacarpal,  but  this  is  probably  due  to 
imperfect  ossification  at  the  proximal  end  ;  for  at  the 
distal  end  the  bones  all  terminated  on  the  same  level, 
showing  that  the  four  outer  digits  were  applied  to 
the  ground  to  support  the  weight  of  the  body.  The 
corresponding  bone  in  the  Horse  and  Oxen  is  carried 
erect,  so  as  to  be  in  a  vertical  line  with  the  bones  of 
the  fore-arm ;  and  the  same  position  prevails  usually, 
though  not  invariably,  with  the  corresponding  bone 
in  the  hind  limb,  while  in  many  clawed  mammals  the 
metacarpus  and  metatarsus  are  both  applied  upon  the 
ground.  In  Pterodactyles  the  metatarsal  bones  are 
preserved  in  the  rock  in  the  same  straight  line  with 
the  smaller  bones  of  the  foot,  or  make  an  angle  with 
the  shin  bone,  leading  to  the  conviction  that  the  bones 
of  the  foot  were 'applied  to  the  ground  as  in  Man, 
and  sometimes  as  in  the  Dog,  and  were  thus  modified 
for  leaping.  Just  as  the  human  metacarpus  is  ex- 
tended in  the  same  line  with  the  bones  of  the  fore- 
arm, and  the  movement  of  jointing  occurs  where  the 
fingers  join  the  metacarpus,  so  Pterodactyles  also 
had  these  bones  differently  modified  in  the  fore  and 
hind  limbs  for  the  functions  of  life.  The  result  is  to 
lengthen  the  fore  limb  as  compared  with  the  hind 


128  DRAGONS    OF   THE   AIR 

limb  by  introducing  into  it  an  elevation  above  the 
ground  which  corresponds  to  the  length  of  the  meta- 
carpus, always  supposing  that  the  animal  commonly 
assumed  the  position  of  a  quadruped  when  upon  the 
earth's  surface. 

This  position  of  the  metacarpus  is  a  remarkable 
difference  from  Birds,  because  when  the  bird's  wing 
is  at  rest  it  is  folded  into  three  portions.  The  upper 
arm  bone  extends  backward,  the  bones  of  the  fore- 
arm are  bent  upon  it  so  as  to  extend  forward,  and 
then  at  the  wrist  the  third  portion,  which  includes 
the  metacarpus  and  finger  bones,  is  bent  backward. 
So  that  the  metacarpus  in  the  Pterodactyle  differs  from 
birds  in  being  in  the  same  line  as  the  bones  of  the 
fore-arm,  whereas  in  birds  it  is  in  the  same  line  with 
the  digit  bones  of  the  hand.  It  is  worthy  of  remark 
that  in  Bats,  which  are  so  suggestive  of  Pterodactyles 
in  some  features  of  the  hand,  the  metacarpals  and 
phalanges  are  in  the  same  straight  line ;  so  that  in 
this  respect  the  bat  is  more  like  the  bird.  But  Ptero- 
dactyles in  the  relation  of  these  bones  to  flight  are 
quite  unlike  any  other  animal,  and  have  nothing  in 
common  with  the  existing  animals  named  Reptiles. 

THE    HAND 

From  what  has  just  been  said  it  follows  that  the 
construction  of  the  hand  is  unique.  It  may  be  con- 
trasted with  the  foot  of  a  bird.  The  bone  which 
is  called,  in  the  language  of  anatomists,  the  tarso- 
metatarsus,  and  is  usually  free  from  feathers  and 
covered  with  skin,  is  commonly  carried  erect  in  birds, 
so  that  the  whole  body  is  supported  upon  it;  and 
from  it  the  toes  diverge  outward.  It  is  formed  in 
birds  of  three  separate  bones  blended  together.  In 


SHOULDER-GIRDLE  AND  FORE  LIMB    129 

the  fore  limb  of  the  Pterodactyle  the  metacarpus 
has  the  same  relation  to  the  bones  of  the  fore-arm 
that  the  metatarsus  has  to  the  corresponding  bones 
of  the  leg  in  a  bird.  But  the  three  metacarpal  bones 
in  the  Pterodactyle  remain  distinct  from  each  other, 
perhaps  because  the  main  work  of  that  region  of  the 
skeleton  has  devolved  upon  the  digit  called  the  wing 
finger,  which  is  not  recognised  in  the  bird.  In  the 
Pterodactyles  from  the  Solenhofen  Slate  there  is 
a  progressive  number  of  phalanges  in  the  three  small 
digits  of  the  hand,  which  were  applied  to  the  ground. 
This  number  in  the  great  majority  of  species  follows 
the  formula  of  two  bones  in  the  first,  three  bones  in 
second,  and  four  in  the  third ;  so  that  in  the  innermost 
of  the  clawed  digits  only  one  bone  intervenes  between 
the  metacarpal  and  the  claw.  The  fingers  slightly 
increase  in  length  with  increase  in  number  of  bones 
which  form  them. 

The  terminal  claw  bones  are  unlike  the  claws  of 
Birds  or  Reptiles.    They  are  compressed  from  side  to 


FIG.  45.      CLAW   PHALANGE   FROM   THE   HAND 
IN  ORNI1 HOCHEIRUS.      (Half  natural  size) 

side,  and  extremely  deep  and  strong,  with  evidence  of 
powerful  attachment  for  ligaments,  so  that  they  rather 
resemble  in  their  form  and  large  size  the  claws  of 
some  of  the  carnivorous  fossil  reptiles,  often  grouped 
as  Dinosauria,  such  as  have  been  termed  Aristo- 
suchus  and  Megalosaurus.  In  the  hand  of  the 
Ostrich  the  first  and  second  digits  terminate  in 
claws,  while  the  third  is  without  a  claw.  But  these 

K 


130 


DRAGONS   OF   THE   AIR 


claws  of  the  Ostrich  and  other  birds  are  slender, 
curved,  and  rather  feeble  organs.  In  the  Archoeop- 
teryx,  a  fossil  bird  which  agrees  with  the  Pterodactyles 
in  retaining  the  separate  condition  of  the  metacarpal 
bones  and  in  having  the  same  number  of  phalanges 
in  two  of  the  fingers  of  the  fore  limb,  the  terminal 
claws  are  rather  more  compressed  from  side  to  side, 
and  stronger  than  in  the  Ostrich,  but  not  nearly  so 
strong  as  in  the  Pterodactyle.  The  Archaeopteryx 


Ostrich        Archaeopteryj 


FIG.  46.      METACARPUS  AND   DIGITS   OF  THE   HAND 
IN   BIRDS   WITH   CLAWS 


differs  from  the  Pterodactyle  in  having  no  trace  of  a 
wing  finger.  The  first  metacarpal  bone  is  short, 
as  in  all  birds ;  and  the  first  phalange  scarcely 
lengthens  that  segment  of  the  first  digit  of  the  Bird's 
hand  to  the  same  length  as  the  other  metacarpal 
bones.  It  therefore  was  not  bent  backward  like  the 
first  digit  in  Pterodactyles.  The  wing  finger,  from 
which  the  genius  of  Cuvier  selected  the  scientific 
name — Pterodactyle — for  these  fossils,  yields  their 


SHOULDER-GIRDLE  AND  FORE  LIMB    131 

most  distinctive  character.  It  is  a  feature  which  could 
only  be  partly  paralleled  in  the  Bat,  by  making 
changes  of  structure  which  would  remove  every 
support  to  the  wing  but  the  outermost  digit  of  that 
animal's  hand.  In  the  Bat's  hand  the  membrane  for 
flight  is  extended  chiefly  by  four  diverging  metacarpal 
bones.  There  are  only  two  or  three  phalanges  in  each 
digit  in  its  four  wing  fingers.  In  Pterodactyles  the 
metacarpal  bones  are,  as  we  have  seen,  arranged  in 
close  contact,  and  take  no  part  in  stretching  the  wing. 

THE   WING   FINGER 

In  Birds  there  is  nothing  whatever  to  represent  the 
wing  finger  of  the  Pterodactyle,  for  it  is  an  organ 
external  to  the  finger  bones  of  the  bird,  and  contains 
four  phalanges.  The  first  phalange  is  quite  different 
from  the  others.  Its  length  is  astonishing  when  com- 
pared with  the  small  phalanges  of  the  clawed  fingers. 
The  articular  surface,  which  joins  on  to  the  wing 
metacarpal  bone,  is  a  concave  articulation,  which  fits 
the  pulley  in  which  that  bone  ends.  The  pulley 
articulation  admits  of  an  extension  movement  in 
one  direction  only.  Many  specimens  show  the  wing 
finger  to  be  folded  up  so  as  to  extend  backward. 
The  whole  finger  is  preserved  in  other  specimens 
straightened  out  so  as  to  be  in  line  with  the  meta- 
carpus. This  condition  is  well  seen  in  Professor 
Marsh's  specimen  of  Rhamphorhynchus,  which  has 
the  wing  membrane  preserved,  in  which  all  bones 
of  the  fore-arm  metacarpus  and  wing  finger  are 
extended  in  a  continuous  curve.  The  outer  surface 
of  the  end  of  the  first  bone  of  the  wing  finger 
overlaps  the  wing  metacarpal,  so  that  a  maximum 
of  strength  and  resistance  is  provided  in  the  bony 


132  DRAGONS   OF  THE  AIR 

structures  by  which  the  wing  is  supported.  There 
is,  therefore,  in  flight  only  one  angular  bend  in  the 
limb,  and  that  is  between  the  upper  arm  bone  and 
the  fore-arm. 

An  immense  pneumatic  foramen  is  situate  in  a 
groove  on  the  under  side  of  the  upper  end  of  the 
first  phalange  in  Ornithocheirus,  but  is  absent  in 
specimens  from  the  Kimeridge  clay.  This  bone  is 
long  and  stout.  It  terminates  at  the  lower  end  in 
an  obliquely  truncated  articular  surface.  Specimens 
occur  in  the  Cambridge  Greensand  which  are  2  inches 
broad  at  the  upper  end  and  nearly  i|  inch  wide  at 
the  lower  end.  An  imperfect  bone  from  the  Chalk 
is  14!  inches  long.  The  bones  are  all  flattened. 
Specimens  from  the  Chalk  of  Kansas  at  Munich  are 
28  inches  long.  The  second  phalange  is  concave  at 
the  upper  articular  end  and  convex  in  the  longer 
direction  at  the  lower  end.  The  articular  points  of 
union  between  the  several  phalanges  form  promi- 
nences on  the  under  side  of  the  finger  in  consequence 
of  the  adjacent  bones  being  a  little  widened  at  their 
junction.  It  should  be  mentioned  that  there  is  a 
proximal  epiphysis  or  separate  bone  to  the  first 
phalange,  adjacent  to  the  pulley  joint  of  the  meta- 
carpal  bone,  which  is  like  the  separate  olecranon  pro- 
cess of  the  ulna  of  the  fore-arm.  It  sometimes  comes 
away  in  specimens  from  the  Chalk  and  Cambridge 
Greensand,  leaving  a  large  circular  pit  with  a  de- 
pressed narrow  border.  On  the  outer  side  of  this 
process  is  a  rounded  boss,  which  may  possibly  have 
supported  the  bone,  if  it  were  applied  to  the  ground 
with  the  wing  folded  up,  like  the  wing  of  a  Bat  directed 
upward  and  backward  at  the  animal's  side. 

The  four  bones  of  the  wing  finger  usually  decrease 


SHOULDER-GIRDLE  AND  FORE  LIMB    133 

progressively  in  length,  so  that  in  Rhamphorhynchus, 
in  which  the  length  of  the  animal's  head  only  slightly 
exceeds  3  J  inches,  the  first  phalange  is  nearly  as  long, 
the  second  phalange  is  about  3^  inches,  the  third  2f 
inches,  and  the  fourth  a  little  over  2  inches.  Thus 
the  entire  length  of  the  four  phalanges  slightly  ex- 
ceeds 1 1  inches,  or  rather  more  than  three  times  the 
length  of  the  head.  But  the  fore-arm  and  metacarpus 
in  this  type  only  measure  3  inches.  Therefore  the 
entire  spread  of  wings  could  not  have  been  more 
than  2  feet  9  inches. 

The  largest  Ornithosaur  in  which  accurate  measure- 
ments have  been  made  is  the  toothless  Pterodactyle 
Ornithostoma,  also  named  Pteranodon,  from  North 
America.  In  that  type  the  head  appears  to  have 
been  about  3  or  4  feet  long,  and  the  wing  finger 
exceeded  5  feet;  while  the  length  of  the  fore-arm 
and  metacarpus  exceeded  3  feet.  The  width  of  the 
body  would  not  have  been  more  than  I  foot.  The 
length  of  the  short  humerus,  which  was  about 
1 1  inches,  did  not  add  greatly  to  the  stretch  of  the 
wing ;  so  that  the  spread  of  the  wings  as  stretched 
in  flight  may  be  given  as  probably  not  exceeding 
17  or  1 8  feet.  A  fine  example  of  the  wing  bones  of 
this  animal  quite  as  large  has  been  obtained  by  the 
(British  Museum  Natural  History).  Many  years  ago, 
on  very  fragmentary  materials,  I  estimated  the  wings 
in  the  English  Cretaceous  Ornithocheirus  as  probably 
having  a  stretch  of  20  feet  in  the  largest  specimens, 
basing  the  calculation  partly  upon  the  extent  of  the 
longest  wings  in  existing  birds  relatively  to  their 
bones,  and  partly  upon  the  size  of  the  largest  associ- 
ated bones  which  were  then  known. 


CHAPTER  XII 

EVIDENCES   OF   THE    ANIMAL'S 
HABITS    FROM    ITS   REMAINS 

SUCH  are  the  more  remarkable  characters  of  the 
bones  in  a  type  of  animal  life  which  was  more 
anomalous  than  any  other  which  peopled  the  earth 
in  the  Secondary  Epoch  of  geological  time.  Its 
skeleton  in  different  parts  resembles  Reptiles,  Birds, 
and  Mammals  ;  with  modifications  and  combinations 
so  singular  that  they  might  have  been  deemed  im- 
possible if  Nature's  power  of  varying  the  skeleton 
could  be  limited.  Since  Ornithosaurs  were  provided 
with  wings,  we  may  believe  the  animals  to  some  extent 
to  have  resembled  birds  in  habit.  Their  modes  of 
progression  were  more  varied,  for  the  structures  indi- 
cate an  equal  capacity  for  movement  on  land  as  a 
biped,  or  as  a  quadruped,  with  movement  in  the  air. 
There  is  little  evidence  to  support  the  idea  that  they 
were  usually  aquatic  animals.  The  majority  of  birds 
which  frequent  the  water  have  their  bodies  stored 
with  fat  and  the  bones  of  their  extremities  filled  with 
marrow.  And  a  bird's  marrow  bones  are  stouter  and 
stronger  than  those  which  are  filled  with  air.  There 
are  few,  if  any,  bones  of  Pterodactyles  so  thick  as  to 
suggest  the  conclusion  that  they  contained  marrow, 


EVIDENCES  OF  ANIMAL'S   HABITS    135 

and  the  bones  of  the  extremities  appear  to  have  been 
constructed  on  the  lightest  type  found  among  terres- 
trial birds.  Their  thinness,  except  in  a  few  specimens 
from  the  Wealden  rocks,  is  marvellous ;  and  all  the 
later  Pterodactyles  show  the  arrangement,  as  in  birds-, 
by  which  air  from  the  lungs  is  conveyed  to  the 
principal  bones.  No  Pterodactyle  has  shown  any 
trace  of  the  web-footed  condition  seen  in  birds  which 
swim  on  the  water,  unless  the  diverging  bones  of  the 
hind  foot  in  Rhamphorhynchus  supports  that  infer- 
ence. The  bones  of  the  hind  foot  are  relatively 
small,  and  if  it  were  not  that  a  bird  stands  easily 
upon  one  foot,  might  be  considered  scarcely  adequate 
to  support  the  animal  in  the  position  which  terrestrial 
birds  usually  occupy.  Yet,  as  compared  with  the 
length  and  breadth  of  the  foot  in  an  Ostrich,  the  toes 
of  an  Ornithosaur  are  seen  to  be  ample  for  support. 
These  facts  appear  to  discourage  the  idea  that  the 
animals  were  equally  at  home  on  land  and  water,  and 
in  air. 

Some  light  may  be  thrown  upon  the  animal's  habits 
by  the  geological  circumstances  under  which  the 
remains  are  found.  The  Pterodactyle  named  Dimor- 
phodon,  from  the  Lias  of  the  south  of  England,  is 
associated  with  evidences  of  terrestrial  land  animals, 
the  best  known  of  which  is  Scelidosaurus,  an  ar- 
moured Dinosaur  adapted  by  its  limbs  for  progression 
on  land.  And  the  Pterodactyle  Campylognathus, 
from  the  Lias  of  Whitby,  is  associated  with  trunks 
of  coniferous  trees  and  remains  of  Insects.  So  that 
the  occurrence  of  Pterodactyles  in  a  marine  stratum 
is  not  inconsistent  with  their  having  been  transported 
by  streams  from  off  the  old  land  surface  of  the  Lias, 
on  which  coniferous  trees  grew  and  Dinosaurs  lived. 


136  DRAGONS   OF  THE   AIR 

Similar  considerations  apply  to  the  occurrence  of 
the  Rhamphocephalus  in  the  Stonesfield  Slate  of 
England.  The  deposit  is  not  only  formed  in  shallow 
water,  but  contains  terrestrial  Insects,  a  variety  of 
land  plants,  and  many  Reptiles  and  other  animals 
which  lived  upon  land.  The  specimens  from  the 
Purbeck  beds,  again,  are  in  strata  which  yield  a 
multitude  of  the  spoils  of  a  nearly  adjacent  land 
surface;  while  the  numerous  remains  found  in  the 
marine  Solenhofen  Slate  in  Germany  are  similarly 
associated  with  abundant  evidences  of  varied  types 
of  terrestrial  life.  The  evidence  grows  in  force  from 
its  cumulative  character.  The  Wealden  beds,  which 
yield  many  terrestrial  reptiles  and  so  much  evidence 
of  terrestrial  vegetation,  and  shallow-water  conditions 
of  disposition,  have  afforded  important  Pterodactyle 
remains  from  the  Isle  of  Wight  and  Sussex. 

The  chief  English  deposit  in  which  these  fos'sils 
are  found,  the  Upper  Greensand,  has  afforded 
thousands  of  bones,  battered  and  broken  on  a 
shore,  where  they  have  lain  in  little  associated 
groups  of  remains,  often  becoming  overgrown  with 
small  marine  shells.  Side  by  side  with  them  are 
found  bones  of  true  terrestrial  Lizards  and  Crocodiles 
of  the  type  of  the  Gavial  of  the  Indian  rivers,  many 
terrestrial  Dinosaurs,  and  other  evidences  of  land 
life,  including  fossil  resins,  such  as  are  met  with  in 
the  form  of  amber  or  copal  at  the  present  day. 

The  great  bones  of  Pterodactyles  found  in  the 
Chalk  of  Kent,  near  Rochester,  became  entombed, 
beyond  question,  far  from  a  land  surface.  There  is 
nothing  to  show  whether  the  animals  died  on  land 
and  were  drifted  out  to  sea  like  the  timber  which  is 
found  water-logged  and  sunken  after  being  drilled  by 


EVIDENCES  OF  ANIMAL'S   HABITS    137 

the  ship-worm  (Teredo)  of  that  epoch.  Seeing  the 
power  of 'flight  which  the  animal  possessed,  storms 
may  have  struck  down  travellers  from  time  to  time, 
when  far  from  land. 

Evidence  of  habit  of  another  kind  may  be  found 
in  their  teeth.  They  are  brightly  enamelled,  sharp, 
formidable;  and  are  frequently  long,  overlapping  the 
sides  of  the  jaws.  They  are  organs  which  are  often 
better  adapted  for  grasping  than  for  tearing,  as  may 
be  seen  in  the  inclined  teeth  of  Rhamphocephalus  of 
the  Stonesfield  Slate ;  and  better  adapted  for  killing 
than  tearing,  from  their  piercing  forms  and  cutting 
edges,  in  genera  like  Ornithocheirus  of  the  Greensand. 
The  manner  in  which  the  teeth  were  implanted  and 
carried  is  better  paralleled  by  the  fish-eating  crocodile 
of  Indian  rivers  than  by  the  flesh-eating  crocodiles,  or 
Muggers,  which  live  indifferently  in  rivers  and  the 
sea.  As  the  Kingfisher  finds  its  food  (see  Fig.  20) 
from  the  surface  of  the  water  without  being  in  the 
common  sense  of  the  term  a  water  bird,  so  some 
Pterodactyles  may  have  fed  on  fish,  for  which  their 
teeth  are  well  adapted,  both  in  the  stream  and  by  the 
shore. 

A  Pterodactyle's  teeth  vary  a  good  deal  in  appear- 
ance. The  few  large  teeth  in  the  front  of  the  jaw 
in  Dimorphodon,  associated  with  the  many  small 
vertical  teeth  placed  further  backward,  suggest  that 
the  taking  of  food  may  have  been  a  process  re- 
quiring leisure,  since  the  hinder  teeth  adapted  to 
mincing  the  animal's  meat  are  extremely  small.  The 
way  in  which  the  teeth  are  shaped  and  arranged 
differs  with  the  genera.  In  Pterodactylus  they  are 
short  and  broad  and  few,  placed  for  the  most  part 
towards  the  front  of  the  jaws.  Their  lancet-shaped 


138  DRAGONS   OF   THE   AIR 

form  indicates  a  shear-like  action  adapted  to  dividing 
flesh.  In  the  associated  genus  Rhamphorhynchus 
the  teeth  are  absent  from  the  extremity  of  the  jaw, 
are  slender,  pointed,  spaced  far  apart,  and  extend  far 
backward.  When  the  jaws  of  the  Rhamphorhynchus 
are  brought  together  there  is  always  a  gap  between 
them  in  front,  which  has  led  to  belief  that  the  teeth 
were  replaced  by  some  kind  of  horny  armature  which 
has  perished.  In  the  long-nosed  English  type  of 
Ornithocheirus  the  jaws  are  compressed  together,  so 
that  the  teeth  of  the  opposite  sides  are  parallel  to 
each  other,  with  the  margins  well  filled  with  teeth, 
which  are  never  in  close  contact,  though  occasionally 
closer  and  larger  in  front,  in  some  of  the  forms  with 
thick  truncated  snouts. 

It  is  not  the  least  interesting  circumstance  of  the 
dentition  of  Pterodactyles  that,  associated  in  the 
same  deposits  with  these  most  recent  genera  with 
teeth  powerfully  developed,  there  is  a  genus  named 
Ornithostoma  from  the  resemblance  of  its  mouth  to 
that  of  a  bird  in  being  entirely  devoid  of  teeth.  It 
is  scarcely  possible  to  distinguish  the  remains  of  the 
toothed  and  toothless  skeletons  except  in  the  dentary 
character  of  the  jaws.  There  is  no  evidence  that 
the  toothless  types  ever  possessed  a  tooth  of  any 
sort.  They  were  first  found  in  fragments  in  England 
in  the  Cambridge  Greensand,  but  were  afterwards 
met  with  in  great  abundance  in  the  Chalk  of  Kansas, 
where  the  same  animals  were  named  Pteranodon. 
A  jaw  so  entirely  bird-like  suggests  that  the  digestive 
organs  of  Pterodactyles  may  in  such  toothless  forms 
at  least  have  been  characterised  by  a  gizzard,  which 
is  so  distinctive  of  Birds.  The  absence  of  teeth  in 
the  Great  Ant-eater  and  some  other  allied  Mammals 


EVIDENCES  OF  ANIMAL'S   HABITS    139 

has  transferred  the  function  which  teeth  usually  per- 
form to  the  stomach,  one  part  of  which  becomes 
greatly  thickened  and  muscular,  adapting  itself  to 
the  work  which  it  has  to  perform.  It  is  probable 
that  the  gizzard  may  be  developed  in  relation  to  the 
necessities  which  food  creates,  since  even  Trout,  feed- 
ing on  the  shell-fish  in  some  Irish  lochs,  acquire  such 
a  thickened  muscular  stomach,  and  a  like  modifi- 
cation is  recorded  in  other  fishes  as  produced  by 
food. 

Closely  connected  with  an  animal's  habits  is  the 
protection  to  the  body  which  is  afforded  by  the  skin. 
In  Pterodactyles  the  evidence  of  the  condition  of 
the  skin  is  scanty,  and  mostly  negative.  Sometimes 
the  dense,  smooth  texture  of  the  jaw  bones  indicates 
a  covering  like  the  skin  of  a  Lizard  or  the  hinder  part 
of  the  jaw  of  a  Bird.  Some  jaws  from  the  Cam- 
bridge Greensand  have  the  bone  channeled  over  its 
surface  by  minute  blood  vessels  which  have  im- 
pressed themselves  into  the  bone  more  easily  than 
into  its  covering.  Thus  in  the  species  of  Ornitho- 
cheirus  distinguished  as  microdon  the  palate  is 
absolutely  smooth,  while  in  the  species  named 
niach(zrorhynchus  it  is  marked  by  parallel  impressed 
vascular  grooves  which  diverge  from  the  median 
line.  This  condition  clearly  indicates  a  difference  in 
the  covering  of  the  bone,  and  that  in  the  latter 
species  the  covering  had  fewer  blood  vessels  and 
more  horny  protection  than  in  the  other.  The  tissue 
may  not  have  been  of  firmer  consistence  than  in  the 
palate  of  Mammals.  The  extremity  of  the  beak  is 
often  as  full  of  blood  vessels  as  the  jaw  of  a  Turtle 
or  Crocodile. 


140  DRAGONS   OF   THE   AIR 


COVERING   OF   THE   BODY 

There  is  no  trace  even  in  specimens  from  the 
Solenhofen  or  Stonesfield  Slate  of  any  covering  to 
the  body.  There  are  no  specimens  preserved  like 
mummies,  and  although  the  substance  of  the  wings 
is  found  there  is  no  trace  of  fur  or  feathers,  bones, 
or  scales  on  the  skin.  The  only  example  in  which 
there  is  even  an  appearance  suggesting  feathers  is  in 
the  beautiful  Scaphognathus  at  Bonn,  and  upon  por- 
tions of  the  wing  membrane  of  that  specimen  are 
preserved  a  very  few  small  short  and  apparently 
tubular  bodies,  which  have  a  suggestive  resemblance 
to  the  quills  of  small  undeveloped  feathers.  Such 
evidences  have  been  diligently  sought  for.  Professor 
Marsh,  after  examining  the  wing  membranes  of  his 
specimen  of  Rhamphorhynchus  from  Solenhofen, 
stated  that  the  wings  were  partially  folded  and 
naturally  contracted  into  folds,  and  that  the  surface 
of  the  tissue  is  marked  by  delicate  striae,  which 
might  easily  be  taken  at  first  sight  for  a  thin  coating 
of  hair.  Closer  investigation  proved  the  markings 
to  be  minute  wrinkles  on  the  under  surface  of  the 
wing  membrane.  This  negative  evidence  has  con- 
siderable value,  because  the  Solenhofen  Slate  has 
preserved  in  the  two  known  examples  of  the  bird 
Archaeopteryx  beautiful  details  of  the  structure  of 
the  larger  feathers  concerned  in  flight.  It  has  pre- 
served many  structures  far  more  delicate.  There  is, 
therefore,  reason  for  believing  that  if  the  skin  had 
possessed  any  covering  like  one  of  those  found  in 
existing  vertebrate  animals,  it  could  scarcely  have 
escaped  detection  in  the  numerous  undisturbed  skele- 
tons of  Pterodactyles  which  have  been  examined. 


EVIDENCES  OF  ANIMAL'S   HABITS    141 

The  absence  of  a  recognisable  covering  to  the  skin 
in  a  fossil  state  cannot  be  accepted  as  conclusive 
evidence  of  the  temperature,  habits,  or  affinities  of 
the  animal.  Although  Mammalia  are  almost  en- 
tirely clothed  with  dense  hair,  which  has  never  been 
found  in  a  recognisable  condition  in  a  fossil  state  in 
any  specimen  of  Tertiary  age,  one  entire  order,  the 
Cetacea,  show  in  the  smooth  hairless  skins  of  Whales 
and  Porpoises  that  the  class  may  part  with  the 
typical  characteristic  covering  without  loss  of  tempera- 
ture and  without  intelligible  cause.  That  the  absence 
of  hair  is  not  due  to  the  aquatic  conditions  of  rivers 
or  sea  is  proved  by  other  marine  Mammals,  like  Seals, 
having  the  skin  clothed  with  a  dense  growth  of  hair, 
which  is  not  surpassed  in  any  other  order.  The  fine- 
ness of  the  growth  of  hair  in  Man  gives  a  superficial 
appearance  of  the  skin  being  imperfectly  clothed, 
and  a  similar  skin  in  a  fossil  state  might  give  the 
impression  that  it  was  devoid  of  hair.  There  are 
many  Mammals  in  which  the  skin  is  scantily  clothed 
with  hair  as  the  animal  grows  old.  Neither  the 
Elephant  nor  the  Armadillo  in  a  fossil  state  would  be 
likely  to  have  the  hair  preserved,  for  the  growth  is 
thin  on  the  bony  shields  of  the  living  Armadilloes. 
Yet  the  difficulty  need  be  no  more  inherent  in  the 
nature  of  hair  than  in  that  of  feathers,  since  the  hair 
of  the  Mammoth  and  Rhinoceros  has  been  com- 
pletely preserved  upon  their  skins  in  the  tundras  of 
Siberia,  densely  clothing  the  body.  This  may  go 
to  show  that  the  Pterodactyle  possessed  a  thin 
covering  of  hair,  or,  more  probably,  that  hair 
was  absent.  Since  Reptiles  are  equally  variable  in 
the  clothing  of  the  skin  with  bony  or  horny  plates, 
and  in  sometimes  having  no  such  protection,  it  may 


142  DRAGONS   OF   THE   AIR 

not  appear  singular  that  the  skin  in  Ornithosaurs  has 
hitherto  given  no  evidence  of  a  covering.  From 
analogy  a  covering  might  have  been  expected ; 
feathers  of  Birds  and  hair  of  Mammals  are  non- 
conducting coverings  suited  to  arrest  the  loss  of  heat. 

With  the  evidence,  such  as  it  is,  of  resemblance  of 
Ornithosaurs  to  Birds  in  some  features  of  respiration 
and  flight,  a  covering  to  the  skin  might  have  been 
expected.  Yet  the  covering  may  not  be  necessary 
to  a  high  temperature  of  the  blood.  Since  Dr.  John 
Davy  made  his  observations  it  has  been  known  that 
the  temperature  of  the  Tunny,  above  90°  Fahrenheit, 
is  as  warm  as  the  African  scaly  ant-eater  named  the 
Pangolin,  which  has  the  body  more  amply  protected 
by  its  covering.  This  illustration  also  shows  that 
hot  blood  may  be  produced  without  a  four-celled 
heart,  with  which  it  is  usually  associated,  and  that 
even  if  the  skin  in  Pterodactyles  was  absolutely 
naked  an  active  life  and  an  abundant  supply  of  blood 
could  have  given  the  animal  a  high  temperature. 

The  circumstance  that  in  several  individuals  the 
substance  of  the  wing  membrane  is  preserved  would 
appear  to  indicate  either  that  it  was  exceptionally 
stout  when  there  would  have  been  small  chance  of 
resisting  decomposition,  or  that  its  preservation  is 
due  to  a  covering  which  once  existed  of  fur  or  down 
or  other  clothing  substance,  which  has  proved  more 
durable  than  the  skin  itself. 


f 


CHAPTER  XIII 

ANCIENT   ORNITHOSAURS   FROM 
THE    LIAS 

CUVIER'S  discourse  on  the  revolutions  of  the 
Earth  made  the  Pterodactyle  known  to  English 
readers  early  in  the  nineteenth  century.  Dr.  Buck- 
land,  the  distinguished  professor  of  Geology  at 
Oxford,  discovered  in  1829  a  far  larger  specimen  in 
the  Lias  of  Lyme  Regis,  and  it  became  known  by  a 
figure  published  by  the  Geological  Society,  and  by  the 
description  in  his  famous  Bridgewater  Treatise,  p.  164. 
This  animal  was  tantalising  in  imperfect  preservation. 
The  bones  were  scattered  in  the  clay,  so  as  to  give  no 
idea  of  the  animal's  aspect.  Knowledge  of  its  limbs 
and  body  has  been  gradually  acquired ;  and  now,  for 
some  years,  the  tail  and  most  parts  of  the  skeleton 
have  been  well  known  in  this  oldest  and  most 
interesting  British  Pterodactyle. 

Sir  Richard  Owen  after  some  time  separated  the 
fossil  as  a  distinct  genus,  named  Dimorphodon ;  for 
it  was  in  many  ways  unlike  the  Pterodactyles  de- 
scribed from  Bavaria.  The  name  Dimorphodon  indi- 
cated the  two  distinct  kinds  of  teeth  in  the  jaws, 
a  character  which  is  still  unparalleled  among  Ptero- 
dactyles of  newer  age.  There  are  a  few  large  pointed, 
143 


144  DRAGONS   OF   THE   AIR 

piercing  and  tearing  teeth  in  the  front  of  the  jaws, 
with  smaller  teeth  further  back,  placed  among  the 
tearing  teeth  in  the  upper  jaw ;  while  in  the  lower 
jaw  the  small  teeth  are  continuous,  close-set,  and 
form  a  fine  cutting  edge  like  a  saw. 

The  Dimorphodon  has  a  short  beak,  a  deep  head, 
and  deep  lower  jaw,  which  is  overlapped  by  the  cheek 
bones.  The  side  of  the  head  is  occupied  by  four 
vacuities,  separated  by  narrow  bars  of  bone.  First,  in 
front,  is  the  immense  opening  for  the  nostril,  triangular 
in  form,  with  the  long  upper  side  following  the  rounded 
curve  of  the  face.  A  large  triangular  opening  inter- 


ne. 49.      LEFT  SIDE  OF  DIMORPHODON   (RESTORED)  AT  REST 

venes  between  the  nose  hole  and  the  eye  hole,  scarcely 
smaller  than  the  former,  but  much  larger  than  the 
orbit  of  the  eye.  The  eye  hole  is  shaped  like  a  kite 
or  inverted  pear.  Further  back  still  is  a  narrower  ver- 
tical opening  known  as  the  lateral  or  inferior  temporal 
vacuity.  The  back  of  the  head  is  badly  preserved, 
The  two  principal  skulls  differ  in  depth,  probably 
from  the  strains  under  which  they  were  pressed  flat 
in  the  clay.  A  singular  detail  of  structure  is  found 
in  the  extremity  of  the  lower  jaw,  which  is  turned 
slightly  downward,  and  terminates  in  a  short  toothless 


ORNITHOSAURS  FROM  THE  LIAS     145 

point.  The  head  of  Dimorphodon  is  about  eight  inches 
long. 

The  neck  bones  are  of  suitable  stoutness  and  width 
to  support  the  head.  The  bones  are  yoked  together 
by  strong  processes.  The  neck  was  about  6  inches 
long,  did  not  include  more  than  seven  bones,  and 
appeared  short  owing  only  to  the  depth  and  size  of 
the  head.  The  length  of  the  backbone  which  sup- 
ported the  ribs  was  also  about  6  inches.  Its  joints 
are  remarkably  short  when  compared  with  those  of 
the  neck.  The  tail  is  about  20  inches  long. 

The  extreme  length  of  the  animal  from  the  tip 
of  the  nose  to  the  end  of  the  tail  may  have  been 
3  feet  4  inches,  supposing  it  to  have  walked  on  all 
fours  in  the  manner  of  a  Reptile  or  Mammal.  This 
may  have  been  a  common  position,  but  Dimorpho- 
don may  probably  also  have  been  a  biped.  Before 
1875,  when  the  first  restoration  appeared  in  the 
Illustrated  London  News,  the  legs  had  been  regarded 
as  too  short  to  have  supported  the  animal,  standing 
upon  its  hind  limbs.  They  are  here  seen  to  be  well 
adapted  for  such  a  purpose.  The  upper  leg  bone  is 
3^  inches  long,  the  lower  leg  bone  is  4^  inches 
long,  and  the  singularly  strong  instep  bones  are 
firmly  packed  together  side  by  side  as  in  a  leap- 
ing or  jumping  Mammal,  and  measure  ij  inches 
in  length.  Dimorphodon  differs  from  several  other 
Pterodactyles  in  having  the  hind  limb  provided 
with  a  fifth  outermost  short  instep  bone,  to  which 
two  toe  bones  are  attached.  These  bones  are  elon- 
gated in  a  way  that  may  be  compared,  on  a  small 
scale,  with  the  elongation  of  the  wing  finger  in  the 
fore  limb.  The  digit  was  manifestly  used  in  the  same 
way  as  the  wing  finger,  in  partial  support  of  a  flying 


146  DRAGONS   OF   THE   AIR 

membrane,  though  its  direction  may  have  been  up- 
ward and  outward,  rather  than  inward.  There  is  no 
evidence  of  a  pulley  joint  between  the  metatarsal 
and  the  adjacent  phalange. 

The  height  of  the  Dimorphodon,  standing  on  its 
hind  legs  in  the  position  of  a  Bird,  with  the  wings 
folded  upon  the  body  in  the  manner  of  a  Bird,  was 
about  20  inches.  An  ungainly,  ill-balanced  animal 
in  aspect,  but  not  more  so  than  many  big-headed 
birds,  and  probably  capable  of  resting  upon  the  instep 
bones  as  many  birds  do.  The  chief  point  of  varia- 
tion from  the  Pterodactyle  wing  is  in  the  relative 
length  of  the  metacarpus  in  Dimorphodon.  It  is 
shorter  than  the  other  bones  in  the  wing,  never 
exceeding  i|  inches.  The  total  length  of  all 
the  arm  bones  down  to  the  point  where  the  meta- 
carpus might  have  touched  the  ground,  or  where 
the  wing  finger  is  bent  upon  it,  is  a'bout  9  inches, 
which  gives  a  length  of  less  than  6  inches  below 
the  upper  arm  bone.  The  four  bones  of  the  wing 
finger  measure,  from  the  point  where  the  first  bone 
bends  upon  the  metacarpus,  less  than  18  inches. 
So  that  the  wings  could  only  have  been  carried 
in  the  manner  of  the  wings  of  a  Bat,  folded  at  the 
side  and  directed  obliquely  over  the  back  when  the 
animal  moved  on  all  fours.  Its  body  would  appear 
to  have  been  raised  high  above  the  ground,  in  a 
manner  almost  unparalleled  in  Reptiles,  and  com- 
parable to  Birds  and  Mammals.  Dimorphodon  is  to 
be  imagined  in  full  flight,  with  the  body  extended 
like  that  of  a  Bird,  when  the  wings  would  have 
had  a  spread  from  side  to  side  of  about  4  feet  4 
inches.  As  in  other  animals  of  this  group,  the  three 
claws  on  the  front  feet  are  larger  than  the  similar 


i 


ORNITHOSAURS  FROM  THE  LIAS     147 

four  claws  on  the  hind  feet;  as  though  the  fingers 
might  have  functions  in  grasping  prey,  which  were 
not  shared  by  the  toes. 

The  restorations  give  faithful  pictures  of  the  skele- 
ton, and  the  form  of  the  body  is  built  upon  the  indi- 
cations of  muscular  structure  seen  in  the  bones. 

A  second  English  Pterodactyle  is  found  in  the 
Upper  Lias  of  Whitby.  It  is  only  known  from 
an  imperfect  skull,  published  in  1888.  It  has  the 
great  advantage  of  preserving  the  bones  in  their 
natural  relations  to  each  other,  and  with  a  length  of 
head  probably  similar  to  Dimorphodon  shows  that 
the  depth  at  the  back  of  the  eye  was  much  less ;  and 
the  skull  wants  the  arched  contour  of  face  seen  in 
Dimorphodon.  The  head  has  the  same  four  lateral 
vacuities,  but  the  nostril  is  relatively  small  and  elon- 
gated, extending  partly  above  the  oval  antorbital 
opening,  which  was  larger.  There  is  thus  a  difference 
of  proportion,  but  it  is  precisely  such  as  might  result 
from  the  species  having  the  skull  flatter.  The  head 
is  easily  distinguished  by  the  small  nostril,  which 
is  smaller  than  the  orbit  of  the  eye.  The  animal 
is  referred  to  another  genus.  The  quadrate  bones 
which  give  attachment  to  the  lower  jaw  send  a  process 
inward  to  meet  the  bones  of  the  palate,  which  differ 
somewhat  from  the  usual  condition.  Two  bony  rods 
extend  from  the  quadrate  bones  backward  and  up- 
ward to  the  sphenoid,  and  two  more  slender  bones 
extend  from  the  quadrate  bones  forward,  and  con- 
verge in  a  V-shape,  to  define  the  division  between 
the  openings  of  the  nostrils  on  the  palate.  The 
V-shaped  bone  in  front  is  called  the  vomer,  while 
the  hinder  part  is  called  pterygoid.  The  bones  that 
extend  backward  to  the  sphenoid  are  not  easily  iden- 


148  DRAGONS   OF   THE   AIR 

tified.  This  animal  is  one  of  the  most  interesting 
of  Pterodactyles  from  the  very  reptilian  character 
exhibited  in  the  back  of  the  head,  which  appears  to 
be  different  from  other  specimens,  which  are  more 
like  a  bird  in  that  region.  Yet  underneath  this 
reptilian  aspect,  with  the  bony  bar  at  the  side  of  the 
temporal  region  of  the  head  formed  by  the  squamosal 
and  quadrate  bones,  defining  the  two  temporal  vacui- 
ties as  in  Reptiles,  a  mould  is  preserved  of  the 
cavity  once  occupied  by  the  brain,  showing  the  chief 
details  of  structure  of  that  organ,  and  proving  that 
in  so  far  as  it  departs  from  the  brain  of  a  Bird  it 
appears  to  resemble  the  brain  of  a  Mammal,  and  is 
unlike  the  brain  of  a  Reptile. 

The  Pterodactyles  from  the  Lias  of  Germany  are 
similar  to  the  English  types,  in  so  far  as  they  can  be 
compared.  In  1878  I  had  the  opportunity  of  study- 
ing those  which  were  preserved  in  the  Castle  at  Banz, 
which  Professor  Andreas  Wagner,  in  1860,  referred  to 
the  new  genus  Dorygnathus.  The  skull  is  unknown, 
but  the  lower  jaw,  6|  inches  long,  is  less  than  2|  inches 
wide  at  the  articulation  with  the  quadrate  bone  in  the 
skull.  The  depth  of  the  lower  jaw  does  not  exceed 
\  inch,  so  that  it  is  in  marked  contrast  to  Buckland's 
Dimorphodon.  The  symphysis,  which  completely 
blends  the  rami  of  the  jaw,  is  short.  As  far  as  it 
extends  it  contains  large  tearing  teeth,  followed  by 
smaller  teeth  behind,  like  those  of  Dimorphodon. 
But  this  German  fossil  appears  to  differ  from  the 
English  type  in  having  the  front  of  the  lower  jaw,  for 
about  f  inch,  compressed  from  side  to  side  into  a 
sharp  blade  or  spear,  more  marked  than  in  any 
other  Pterodactyle,  and  directed  upward  instead  of 
downward  as  in  Dimorphodon.  Nearly  all  the 


ORNITHOSAURS  FROM  THE  LIAS     149 

measurements  in  the  skeleton  are  practically  identi- 
cal with  those  of  the  English  Dimorphodon,  and 
extend  to  the  jaw,  humerus,  ulna  and  radius,  wing 
metacarpal,  first  phalange  of  the  wing  finger.  The 
principal  bones  of  the  hind  limb  appear  to  be  a  little 
shorter ;  but  the  scapula  and  coracoid  are  slightly 
larger.  All  these  bones  are  so  similar  in  form  to 
Dimorphodon  that  they  could  not  be  separated  from 


FIG.   53.      LOWER  JAW   OF   DORYGNATHUS 

SEEN   FROM    BELOW 

From  the  Lower  Lias  of  Germany,  showing  the  spear  in  front 
of  the  tooth  sockets 

the  Lyme  Regis  species,  if  they  were  found  in  the 
same  locality. 

Just  as  the  Upper  Lias  in  England  has  yielded  a 
second  Pterodactyle,  so  the  Upper  Lias  in  Germany 
has  yielded  a  skeleton,  to  which  Felix  Plieninger,  in 
1894,  gave  the  name  Campylognathus.  It  is  an  in- 
structive skeleton,  with  the  head  much  smaller  than 
in  Dimorphodon,  being  less  than  6  inches  long,  but, 
unfortunately,  broken  and  disturbed.  A  lower  jaw 


ISO  DRAGONS   OF  THE   AIR 

..          7-'  *• 

gives  the  length  4!  inches.  ,  Like  the  other  Ptero- 
dactyles  from  the  Lias,  it  has  ftie  extremity  of  the 
beak  toothless,  with  larger  teeth  in  the  region  of  the 
symphysis  in  front  and  smaller  teeth  behind.  The  jaw 
is  deeper  than  in  the  Banz  specimen  from  the  Lower 
Lias,  but  not  so  deep  as  in  Dimorphodon.  -^he  teeth 
of  the  upper  jaw  vary  in  size,  and  there  appears  to 
be  an  exceptionally  large  tooth  in  the  position  of 
the  Mammalian  canine  at  the  junction  of  the/ bones 
named  maxillary  and  intermaxillary. 
-*  The  nasal  opening  is  small  and  elongated,  as  in  the 
English  specimen  from  Whitby.  As  in  that  type 
there  is  little  or  no  indication  of  the  convex  contour 
of  the  face  seen  in  Dimorphodon. 

The 'neck  does  not  appear  to  be  preserved.  In  the 
back  the  vertebrae  are  about  -j\  inch  long,  so  that 
twelve,  which  is  the  usual  number,  would  only  occupy 
a  length  of  a  little  more  than  3^  inches.  The  tail  is 
elongated  like  that  of  Dimorphodon,  and  bordered 
in  the  same  way  by  ossified  ligaments.  There  are 
thirty-five  tail  vertebrae.  Those  which  immediately 
follow  the  pelvis  are  short,  like  the  vertebrae  of  the 
back.  But  they  soon  elongate,  and*  reach  a  maxi- 
mum length  of  nearly  ij  inches  at  the  eighth,  and 
then  gradually  diminish  till  the  last  scarcely  *ex- 
ceeds  i  inch  in  length.  The  length  of  the  tail  is 
about  22  inches ;  this  appears  to  be  an  inch  or 
two  longer  than  in  Dimorphodon.  The  longest  rib 
measures  2\  inches,  and  the  shortest  2  inches.  These 
ribs  probably  were  connected  with  the  sternum,  which 
is  imperfectly  preserved. 

The  bones  of  the  limbs  have  about  the  same  length 
as  those  of  Dimorphodon,  so  far  as  -they  can  be  com- 
pared, except"  that  the  ulna  and  radius  are  shorter. 


ORNITHOSAURS  FROM  THE  LIAS     151 

The  wing  metacarpal  is  of  about  the  same  length, 
but  the  first  phalange  of  the  wing  finger  measures 
6\  inches,  the  second  is  about  8£  inches,  the  third 
6J  inches,  and  the  fourth  4f  inches ;  so  that  the  total 
length  of  the  wing  finger  was  about  half  an  inch  short 
of  2  feet.  One  character  especially  deserves  attention 
in  the  apparent  successive  elongation  of  the  first  three 
phalanges  in  the  wing  finger  in  Dimorphodon.  The 
third  phalange  is  the  longest  in  the  only  specimen  in 
which  the  finger  bones  are  all  preserved.  Usually  the 
first  phalange  is  much  longer  than  the  second,  so  that 


FIG.  55.     THE  LEFT  SIDE  OF  THE  PELVIS  OF  DIMORPHODON 
SHOWING  THE  TWO  PREPUBIC  BONES 

it  is  a  further  point  of  interest  to  find  that  this  Ger- 
man type  shares  with  Dimorphodon  a  character  of 
the  wing  finger  which  distinguishes  both  from  some 
members  of  the  group  by  its  short  first  phalange. 

The  pelvis  is  exceptionally  strong  in  Campylo- 
gnathus,  and  although  it  is  crushed  the  bones  mani- 
festly met  at  the  base  of  the  ischium,  while  the  pubic 
bones  were  separated  from  each  other  in  front.  The 
bones  of  the  hind  limb  are  altogether  shorter  in  the 
German  fossil  than  in  Dimorphodon,  especially  in 


152  DRAGONS   OF   THE   AIR 

the  tibia ;  but  the  structure  of  the  metatarsus  is  just 
the  same,  even  to  the  short  fifth  metatarsal  with  its 
two  digits,  only  those  bones  are  extremely  short,  in- 
stead of  being  elongated  as  in  Dimorphodon.  It  is 
therefore  convenient,  from  the  different  proportions 
of  the  body,  that  Campylognathus  may  be  separated 
from  Dimorphodon  ;  but  so  much  as  is  preserved  of 
the  English  specimen  from  the  Upper  Lias  of  Whitby 
rather  favours  the  belief  that  our  species  should  also 
be  referred  to  Campylognathus,  which  had  not  been 
figured  when  the  Whitby  skull  was  referred  to  Scapho- 
gnathus  by  Mr.  Newton.  It  may  be  doubtful  whether 
there  is  sufficient  evidence  to  establish  the  distinct- 
ness of  the  other  German  genus  Dorygnathus,  though 
it  may  be  retained  pending  further  knowledge. 

In  these  characters  are  grounds  for  placing  the 
Lias  Pterodactyles  in  a  distinct  family,  the  Dimor- 
phodontidse,  as  was  suggested  in  1870.  This  evidence 
is  found  in  the  five  metatarsal  bones,  of  which  four 
are  in  close  contact,  the  middle  two  being  slightly 
the  longest,  so  as  to  present  the  general  aspect  of  the 
corresponding  bones  in  a  Mammal  rather  than  a  Bird. 
Secondly,  the  very  slender  fibula,  prolonged  down  the 
length  of  the  shin  bone,  which  ends  in  a  rounded 
pulley  like  the  corresponding  bone  of  a  Bird.  Thirdly, 
the  great  elongation  of  the  third  wing  phalange. 
Fourthly,  the  prolongation  of  the  coracoid  bone  be- 
yond the  articulation  for  the  humerus,  as  in  a  Bird. 
And  the  toothless,  spear-shaped  beak,  and  jaw  with 
large  teeth  in  front  and  small  teeth  behind,  are  also 
distinctive  characters. 


CHAPTER   XIV 

ORNITHOSAURS    FROM    THE 
MIDDLE    SECONDARY    ROCKS 

RHAMPHOCEPHALUS 

THE  Stonesfield  Slate  in  England,  which  corre- 
sponds in  age  with  the  lower  part  of  the  Great 
or  Bath  Oolite,  yields  many  evidences  of  terrestrial 
life — land  plants,  insects,  and  mammals — preserved  in 
a  marine  deposit.  A  number  of  isolated  bones  have 
been  found  of  Pterodactyles,  some  of  them  indicating 
animals  of  considerable  size  and  strength.  The 
nature  of  the  limestone  was  unfavourable  to  the  pre- 
servation of  soft  wing  membranes,  or  even  to  the  bones 
remaining  in  natural  association.  Very  little  is  known 
of  the  head  of  Rhamphocephalus.  One  imperfect  speci- 
men shows  a  long  temporal  region  which  is  wide,  and 
a  very  narrow  interspace  between  the  orbits ;  with  a 
long  face,  indicated  by  the  extension  of  narrow 
nasal  bones.  The  lower  jaw  has  an  edentulous  beak 
or  spear  in  front,  which  is  compressed  from  side  to 
side  in  the  manner  of  the  Liassic  forms,  but  turned 
upward  slightly,  as  in  Dorygnathus  or  Campylo- 
gnathus.  Behind  this  extremity  are  sharp,  tall  teeth, 
few  in  number,  which  somewhat  diminish  in  size  as 
they  extend  backward,  and  do  not  suddenly  change 
'53 


154  DRAGONS   OF  THE   AIR 

to  smaller  series,  as  in  the  Lias  genera.  A  few  small 
vertebrae  have  been  found,  indicating  the  neck  and 
back.  The  sacrum  consists  of  five  vertebrae.  One 
small  example  has  a  length  of  only  an  inch.  It  is 
a  little  narrower  behind  than  in  front,  and  would  be 
consistent  with  the  animal  having  had  a  long  tail, 
which  I  believe  to  have  been  present,  although  I 
have  not  seen  any  caudal  vertebrae.  The  early  ribs 
are  like  the  early  ribs  of  a  Crocodile  or  Bird  in  the 
well-marked  double  articulation.  The  later  ribs 
appear  to  have  but  one  head.  V-shaped  abdominal 
ribs  are  preserved.  Much  of  the  animal  is  unknown. 
The  coracoid  seems  to  have  been  directed  forward, 
and,  as  in  a  bird,  it  is  2\  inches  long.  The  humerus 
is  3^  inches  long,  and  the  fore -arm  measured  6 
inches,  so  that  it  was  relatively  longer  than  in  Dimor- 
phodon.  The  metacarpus  is  if  inches  long.  The 
wing  finger  was  exceptionally  long  and  strong.  Pro- 
fessor Huxley  gave  its  length  at  29  inches.  My  own 
studies  lead  to  the  conclusion  that  the  first  finger 
bone  of  the  wing  was  the  shorter,  and  that  although 
they  did  not  differ  greatly  in  length,  the  second  was 
probably  the  longest,  as  in  Campylognathus. 

Professor  Huxley  makes  the  second  and  third 
plalanges  /f  inches  long,  and  the  first  only  about 
%  inch  shorter,  while  the  fourth  phalange  is  6i  inches. 
These  measurements  are  based  upon  some  specimens 
in  the  Oxford  University  Museum.  There  is  only 
one  first  phalange  which  has  a  length  of  7f  inches. 
The  others  are  between  5  and  6  inches,  or  but  little 
exceed  4  inches ;  so  that  as  all  the  fourth  phalanges 
which  are  known  have  a  length  of  6J  inches,  it  is 
possible  that  the  normal  length  of  the  first  phalange 
in  the  larger  species  was  5^  inches.  The  largest 


FROM   MIDDLE  SECONDARY  ROCKS    155 

of  the  phalanges  which  may  be  classed  as  second  or 
third  is  8|  inches,  and  that,  I  suppose,  may  have  been 
associated  with  the  7f  inches  first  phalange.  But 
the  other  bones  which  could  have  had  this  position 
all  measure  5|  and  7f  inches.  The  three  .species 
indicated  by  finger  bones  may  have  had  the  measure- 
ments : — 

Phalanges  of  the  wing  finger 


The  femur  is  represented  by  many  examples — one 
3|  inches  long,  and  others  less  than  3  inches  long 
(2^).  In  Campylognathus,  which  has  so  much  in 
common  with  the  jaw  and  the  wing  bones  in  size, 
the  upper  leg  bone  is  2T8<y  inches.  Therefore  if  we 
assign  the  larger  femur  to  the  larger  wing,  the  femur 
will  be  relatively  longer  in  all  species  of  Rhampho- 
cephalus  than  in  Campylognathus.  Only  one  ex- 
ample of  a  tibia  is  preserved.  It  is  3|  inches  long, 
or  only  ^  inch  shorter  than  the  bone  in  Campylo- 
gnathus, which  has  the  femur  2T%-  inches,  so  that  I 
refer  the  tibia  of  Rhamphocephalus  to  the  species 
which  has  the  intermediate  length  of  wing.  These 
coincidences  with  Campylognathus  establish  a  close 
affinity,  and  may  raise  the  question  whether  the 
Upper  Lias  species  may  not  be  included  in  the 
Stonesfield  Slate  genus  Rhamphocephalus. 

The  late  Professor  Phillips,  in  his  Geology  of  Oxford, 
attempted  a  restoration  of  the  Stonesfield  Ornitho- 
saur,  and  produced  a  picturesque  effect  (p.  164);  but 
no  restoration  is  possible  without  such  attention  to 
the  proportions  of  the  bones  as  we  have  indicated. 


156  DRAGONS   OF   THE   AIR 

OXFORD    CLAY 

A  few  bones  of  flying  reptiles  have  been  found  in 
the  Lower  Oxford  Clay  near  Peterborough,  and  others 
in  the  Upper  Oxford  Clay  at  St.  Ives,  in  Huntingdon- 
shire. A  single  tail  vertebra  from  the  Middle  Oxford 
Clay,  near  Oxford,  long  since  came  under  my  own 
notice,  and  shows  that  these  animals  belong  to  a 
long-tailed  type  like  Campylognathus.  The  cervical 
vertebrae  are  remarkable  for  being  scarcely  longer  than 
the  dorsal  vertebrae  ;  an'd  the  dorsal  are  at  least  half 
as  long  again  as  is  usual,  having  rather  the  proportion 
of  bones  in  the  back  of  a  crocodile. 

LITHOGRAPHIC    SLATE 

Long-tailed  Pterodactyles  are  beautifully  preserved 
in  the  Lithographic  Limestone  of  the  south  of  Bavaria, 
at  Solenhofen,  and  the  quarries  in  its  neighbourhood, 
often  with  the  skeleton  or  a  large  part  of  it  flattened 
out  in  the  plane  of  bedding  of  the  rock.  Fine  skele- 
tons are  preserved  in  the  superb  museum  at  Munich, 
at  Heidelberg,  Bonn,  Haarlem,  and  London,  and  are 
all  referred  to  the  genus  Rhamphorhynchus  or  to 
Scaphognathus.  It  is  a  type  with  powerfully  de- 
veloped wings  and  a  .long,  stiff  tail,  very  similar  to 
that  of  Dimorphodon,  so  that  some  naturalists  refer 
both  to  the  same  family.  There  is  some  resemblance. 

The  type  which  is  most  like  Dimorphodon  is  the 
celebrated  fossil  at  Bonn,  sometimes  called  Pterodac- 
tylus  crassirostris,  which  in  a  restored  form,  with  a 
short  tail,  has  been  reproduced  in  many  text-books. 
No  tail  is  preserved  in  the  slab,  and  I  ventured  to 
give  the  animal  a  tail  for  the  first  time  in  a  restora- 
tion (p.  163)  published  by  the  Illustrated  London  News 
in  1875,  which  accompanied  a  report  of  a  Royal 


FROM   MIDDLE  SECONDARY  ROCKS    157 

Institution  lecture.  Afterwards,  in  1882,  Professor 
Zittel,  of  Munich,  published  the  same  conclusion. 
The  reason  for  restoring  the  tail  was  that  the  animal 
had  the  head  constructed  in  the  same  way  as 
Pterodactyles  with  a  long  tail,  and  showed  differences 
from  types  in  which  the  tail  is  short ;  and  there 
is  no  known  short -tailed  Pterodactyle,  with  wrist 
and  hand  bones,  such  as  characterise  this  animal. 
The  side  of  the  face  has  a  general  resemblance  to 
the  Pterodactyles  from  the  Lias,  for  although  the 
framework  is  firmer,  the  four  apertures  in  the  head 
are  similarly  placed.  The  nostril  is  rather  small  and 
elongated,  and  ascends  over  the  larger  antorbital 
vacuity.  The  orbit  for  the  eye  is  the  largest  opening 
in  the  head,  so  that  these  three  apertures  successively 
increase  in  size,  and  are  followed  by  the  vertically 
elongated  post-orbital  vacuity.  The  teeth  are  widely 
spaced  apart,  and  those  in  the  skull  extend  some 
distance  backward  to  the  end  of  the  maxillary  bone. 
There  are  few  teeth  in  the  lower  jaw,  and  they  corre- 
spond to  the  large  anterior  teeth  of  Dimorphodon, 
there  being  no  teeth  behind  the  nasal  opening.  The 
lower  jaw  is  straight,  and  the  extremities  of  the 
jaws  met  when  the  mouth  was  closed.  The  breast 
bone  does  not  show  the  keel  which  is  so  remarkable 
in  Rhamphorhynchus,  which  may  be  attributed  to 
its  under  side  being  exposed,  so  as  to  exhibit  the 
pneumatic  foramina. 

The  ribs  have  double  heads,  more  like  those  of  a 
Crocodile  in  the  region  of  the  back  than  is  the  case 
with  the  bird-like  ribs  from  Stonesfield.  The  second 
joint  in  the  wing  finger  may  be  longer  than  the  first 
— a  character  which  would  tend  to  the  association  of 
this  Pterodactyle  with  species  from  the  Lias ;  a  relation 


158  DRAGONS   OF   THE   AIR 

to  which  attention  was  first  drawn  by  Mr.  E.  T.  New- 
ton, who  described  the  Whitby  skull. 

The  Pterodactyles  from  the  Solenhofen  Slate  which 
possess  long  tails  have  a  series  of  characters  which  show 
affinity  with  the  other  long-tailed  types.  The  jaws  are 
much  more  slender.  The  orbit  of  the  eye  in  Rhampho- 
rhynchus  is  enormously  large,  and  placed  vertically 
above  the  articulation  for  the  lower  jaw.  Immediately 
in  front  of  the  eye  are  two  small  and  elongated  open- 
ings, the  hinder  of  which,  known  as  the  antorbital 
vacuity,  is  often  slightly  smaller  than  the  nostril,  which 
is  placed  in  the  middle  length  of  the  head,  or  a  little 
further  back,  giving  a  long  dagger-shaped  jaw,  which 
terminates  in  a  toothless  spear.  The  lower  jaw  has 
a  corresponding  sharp  extremity.  The  teeth  are 
directed  forward  in  a  way  that  is  quite  exceptional. 
Notwithstanding  the  massiveness  and  elongation  of 
the  neck  vertebrae,  which  are  nearly  twice  as  long  as 
those  of  the  back,  the  neck  is  sometimes  only  about 
half  the  length  of  the  skull. 

All  these  long-tailed  species  from  the  Lithographic 
Stone  agree  in  having  the  sternum  broad,  with  a  long 
strong  keel,  extending  far  forward.  The  coracoid 
bones  extend  outward  like  those  of  a  Crocodile,  so 
as  to  widen  the  chest  cavity  instead  of  being  carried 
forward  as  the  bones  are  in  Birds.  These  bones  in  this 
animal  were  attached  to  the  anterior  extremity  of  the 
sternum,  so  that  the  keel  extended  in  advance  of  the 
articulation  as  in  other  Pterodactyles.  The  breadth 
of  the  sternum  shows  that,  as  in  Mammals,  the  fore 
part  of  the  body  must  have  been  fully  twice  the 
width  of  the  region  of  the  hip-girdle,  where  the 
slenderer  hind  limbs  were  attached.  The  length 
of  the  fore  limb  was  enormous,  for  although  the  head 


FROM  MIDDLE  SECONDARY  ROCKS    159 

suggests  an  immense  length  relatively  to  the  body, 
nearly  equal  to  neck  and  back  together,  the  head  is 
not  more  than  a  third  of  the  length  of  the  wing 
bones.  The  wing  bones  are  remarkable  for  the  short 
powerful  humerus  with  an  expanded  radial  crest, 
which  is  fully  equal  in  width  to  half  the  length  of  the 
bone.  Another  character  is  the  extreme  shortness 
of  the  metacarpus,  usually  associated  with  immense 
strength  of  the  wing  metacarpal  bone. 

The  hind  limbs  are  relatively  small  and  relatively 
short  The  femur  is  usually  shorter  than  the  humerus, 
and  the  tibia  is  much  shorter  than  the  ulna.  The 
bones  of  the  instep,  instead  of  being  held  together 
firmly  as  in  the  Lias  genera,  diverge  from  each  other, 
widening  out,  though  it  often  happens  that  four  of 
the  five  metatarsals  differ  but  little  in  length.  The 
fifth  digit  is  always  shorter. 

The  hip-girdle  of  bones  differs  chiefly  from  other 
types  in  the  way  in  which  those  bones,  which  have 
sometimes  been  likened  to  the  marsupial  bones,  are 
conditioned.  They  may  be  a  pair  of  triangular  bones 
which  meet  in  the  middle  line,  so  that  there  is  an 
outer  angle  like  the  arm  of  a  capital  Y.  Sometimes 
these  triangular  bones  are  blended  into  a  curved, 
bow-shaped  arch,  which  in  several  specimens  appears 
to  extend  forward  from  near  the  place  of  articulation 
of  the  femur.  This  is  seen  in  fossil  skeletons  at 
Heidelberg  and  Munich.  It  is  possible  that  this 
position  is  an  accident  of  preservation,  and  that  the 
prepubic  bones  are  really  attached  to  the  lower 
border  of  the  pubic  bones. 

Immense  as  the  length  of  the  tail  appears  to  be, 
exceeding  the  skull  and  remainder  of  the  vertebral 
column,  it  falls  far  short  of  the  combined  length  of  the 


160  DRAGONS   OF   THE   AIR 

phalanges  of  the  wing  finger.  The  power  of  flight 
was  manifestly  greater  in  Rhamphorhynchus  than  in 
other  members  of  the  group,  and  all  the  modifica- 
tions of  the  skeleton  tend  towards  adaptation  of  the 
animals  for  flying.  The  most  remarkable  modification 
of  structure  at  the  extremity  of  the  tail  was  made 
known  by  Professor  Marsh  in  a  vertical,  leaf- like 
expansion  in  this  genus,  which  had  not  previously 
been  observed  (p.  161).  The  vertebrae  go  on  steadily 
diminishing  in  length  in  the  usual  way,  and  then 
the  ossified  structures  which  bordered  the  tail  bones 
and  run  parallel  with  the  vertebrae  in  all  the  Rham- 
phorhynchus family,  suddenly  diverge  downward  and 
upward  at  right  angles  to  the  vertebrae,  forming  a 
vertical  crest  above  and  a  corresponding  keel  below ; 
and  between  these  structures,  which  are  identified 
with  the  neural  spines  and  chevron  bones  of  ordinary 
vertebrae,  the  membrane  extends,  giving  the  extremity 
of  the  tail  a  rudder-like  feature,  which,  from  know- 
ledge of  the  construction  of  the  tail  of  a  child's  kite, 
may  well  be  thought  to  have  had  influence  in  direct- 
ing and  steadying  the  animal's  movements.  There 
are  many  minor  features  in  the  shoulder-girdle,  which 
show  that  the  coracoid,  for  example,  was  becoming 
unlike  that  bone  in  the  Lias,  though  it  still  continues 
to  have  a  bony  union  with  the  elongated  shoulder- 
blade  of  the  back. 

The  great  German  delineator  of  these  animals,  Von 
Meyer,  admitted  six  different  species.  Mr.  Newton 
and  Mr.  Lydekker  diminish  the  number  to  four.  It  is 
not  easy  to  determine  these  differences,  or  to  say  how 
far  the  differences  observed  in  the  bones  characterise 
species  or  genera.  It  is  certain  that  there  is  one 
remarkable  difference  from  other  and  older  Ptero- 


FROM  MIDDLE  SECONDARY  ROCKS    163 

dactyles,  in  that  the  last  or  fourth  bone  in  the  wing 
finger  is  usually  slightly  longer  than  the  third  bone, 
which  precedes  it.  There  is  a  certain  variability  in 
the  specimens  which  makes  discussion  of  their 
characters  difficult,  and  has  led  to  some  forms  being 
regarded  as  varieties,  while  others,  of  which  less 
material  is  available,  are  classed  as  species.  I  am 
disposed  to  say  that  some  of  the  confusion  may 
have  resulted  from  specimens  being  wrongly  named. 


FIG.  57.      RESTORATION  OF  THE  SKELETON  OF 

SCAPHOGNA  THUS  CRJSS1ROSTRIS 

Published  in  the  Illustrated  London  News  in  1875.     In  which  a  tail  is 
shown  on  the  evidence  of  the  structure  of  the  head  and  hand 

Thus,  there  is  a  Rhamphorhynchus  called  curti- 
manus,  or  the  form  with  the  short  hand.  It  is 
represented  by  two  types.  One  of  these  appears  to 
have  the  humerus  short,  the  ulna  and  radius  long, 
and  the  finger  bones  long  ;  the  other  has  the  humerus 
longer,  the  ulna  much  shorter,  and  the  finger  bones 
shorter.  They  are  clearly  different  species,  but  the 
second  variety  agrees  in  almost  every  detail  with 
a  species  named  hirundinaceus,  the  swallow-like 
Rhamphorhynchus.  This  identification  shows,  not 


164 


DRAGONS    OF   THE    AIR 


that  the  latter  is  a  bad  species,  but  that  curtimanus 
is  a  distinct  species  which  had  sometimes  been  con- 
founded with  the  other.  While  most  of  these 
specimens  show  a  small  but  steady  decrease  in  the 
length  of  the  several  wing  finger  bones,  the  species 
called  Gemmingi  has  the  first  three  bones  absolutely 
equal  and  shorter  than  in  the  species  curtimanus, 


FIG.  58.      SIX    RESTORATIONS 

1.  Ramphocephalus.     Stonesfield  Slate.     John  Phillips,  1871 

2.  Rhamphorhynchus.     O.  C.  Marsh,  1882 

3.  Rhamphorhynchus.     V.  Zittel,  1882 

4.  Omithostoma.     Williston,  1897 

5.  Dimorpbodon.     Buckland,  1836.     Tail  then  unknown 

6.  Ornithocheirus.     H.  G.  Seeley,  1865 

longimanus,  or  hirundinaceus.  In  the  same  way, 
on  the  evidence  of  facts,  I  find  myself  unable  to  join 
in  discarding  Professor  Marsh's  species  phyllurus, 
on  account  of  the  different  proportions  of  its  limb 
bones.  The  humerus,  metacarpus,  and  third  phalange 


FROM  MIDDLE  SECONDARY  ROCKS    165 

of  the  wing  finger  in  Rhamphorhynchus  phyllnrus 
are  exceptionally  short  as  compared  with  other 
species.  Everyone  agrees  that  the  species  called 
longicaudus  is  a  distinct  one,  so  that  it  is  chiefly  in 
slight  differences  in  the  proportions  of  constituent 
parts  of  the  skeleton  that  the  types  of  the  Rham- 
phorhynchus are  distinguished  from  each  other. 
I  cannot  quite  concur  with  either  Professor  Zittel 
(Fig.  58,  3)  or  Professor  Marsh  (Fig.  58,  2)  in  the 
expansion  which  they  give  to  the  wing  membrane 
in  their  restorations ;  for  although  Professor  Zittel 
represents  the  tail  as  free  from  the  hind  legs,  while 
Professor  Marsh  connects  them  together,  they  both 
concur  in  carrying  the  wing  membrane  from  the 
tip  of  the  wing  finger  down  to  the  extremity  of  the 
ankle  joint.  I  should  have  preferred  to  carry  it  no 
further  down  the  body  than  the  lower  part  of  the 
back,  there  being  no  fossil  evidence  in  favour  of  this 
extension  so  far  as  specimens  have  been  described. 
Neither  the  membranous  wings  figured  by  Zittel  nor 
by  Marsh  would  warrant  so  much  body  membrane  as 
the  Rhamphorhynchus  has  been  credited  with.  I 
have  based  my  restoration  (p.  161)  of  the  skeleton 
chiefly  on  Rhamphorhynchus  phyllurus. 

THE   SHORT-TAILED   TYPES 

The  Pterodactylia  are  less  variable ;  and  the  varia- 
tion among  the  species  is  chiefly  confined  to  relative 
length  of  the  head,  length  of  the  neck,  and  the 
height  of  the  body  above  the  ground.  The  tail  is 
always  so  short  as  to  be  inappreciable.  Many  of  the 
specimens  are  fragmentary,  and  the  characters  of  the 
group  are  not  easily  determined  without  careful 
comparisons  and  measurements.  The  bones  of  the 


1 66  DRAGONS   OF   THE   AIR 

fore  limb  and  wing  finger  are  less  stout  than  in 
the  Rhamphorhynchus  type,  while  the  femur  is 
generally  a  little  longer  than  the  humerus,  and  the 
wing  finger  is  short  in  comparison  with  its  condition 
in  Rhamphorhynchus.  These  short-tailed  Ptero- 
dactyles  give  the  impression  of  being  active  little 
animals,  having  very  much  the  aspect  of  birds,  upon 
four  legs  or  two.  The  neck  is  about  as  long  as  the 
lower  jaw,  the  antorbital  vacuity  in  the  head  is  im- 
perfectly separated  from  the  much  larger  nasal  open- 
ing, the  orbit  of  the  eye  is  large  and  far  back,  the 
teeth  are  entirely  in  front  of  the  nasal  aperture,  and 
the  post-orbital  vacuity  is  minute  and  inconspicuous. 
The  sternum  is  much  wider  than  long,  and  no  speci- 
mens give  evidence  of  a  manubrium.  The  finger 
bones  progressively  decrease  in  length.  The  pre- 
pubic  bones  have  a  partially  expanded  fan-like  form, 
and  never  show  the  triradiate  shape,  and  are  never 
anchylosed.  About  fifteen  different  kinds  of  Ptero- 
dactyles  have  been  described  from  the  Solenhofen 
Slate,  mostly  referred  to  the  genus  Pterodactylus, 
which  comprises  forms  with  a  large  head  and  long 
snout.  Some  have  been  placed  in  a  genus  (Orni- 
thocephalus,  or  Ptenodracon)  in  which  the  head 
is  relatively  short.  The  majority  of  the  species 
are  relatively  small.  The  skull  in  Ornithocephalus 
brevirostris  is  only  I  inch  long,  and  the  animal 
could  not  have  stood  more  than  ij  inches  to  its  back 
standing  on  all  fours,  and  but  little  over  2\  inches 
standing  as  a  biped,  on  the  hind  limbs. 

A  restoration  of  the  species  called  Pterodactylus 
scolopaciceps,  published  in  1875  in  the  Illustrated 
London  News  in  the  position  of  a  quadruped,  shows 
an  animal  a  little  larger,  with  a  body  2|  inches  high 


FROM  MIDDLE  SECONDARY  ROCKS    167 

and  6  to  7  inches  long,  with  the  wing  finger  4!  inches 
long.  Larger  animals  occur  in  the  same  deposit,  and 
in  one  named  Pterodactylus  grandis  the  leg  bones 
are  a  foot  long ;  and  such  an  animal  may  have  been 
nearly  a  foot  in  height  to  its  back,  standing  as  a 
quadruped,  though  most  of  these  animals  had  the 


FIG.  59.      RESTORATION   OF  THE  SKELETON  OF 

PTEKODRACON  BREYIROSTR1S 
From  the  Solenhofen  Slate.     The  fourth  joint  of  the  wing  finger  appears  to 


Slate.     The  fourth  joint  of  the  wing  finger  a 
s  not  been  restored  in  the  figure.    (Natural  siz 


neck  flexible  and  capable  of  being  raised  like  the 
neck  of  a  Goose  or  a  Deer  (p.  30),  and  bent  down 
like  a  Duck's  when  feeding. 

The  type  of  the  genus  Pterodactylus  is  the  form 
originally  described  by  Cuvier  as  Pterodactylus  longi- 
rostris  (p.  28).  It  is  also  known  as  P.  antiquus,  that 
name  having  been  given  by  a  German  naturalist  after 
Cuvier  had  invented  the  genus,  and  before  he  had 


1 68  DRAGONS   OF   THE   AIR 

named  the  species.  There  are  some  remarkable 
features  in  which  Cuvier's  animal  is  distinct  from 
others  which  have  been  referred  to  the  same 
genus.  Thus  the  head  is  4^  inches  long,  while 
the  entire  length  of  the  backbone  to  the  ex- 
tremity of  the  tail  is  only  6J  inches,  and  one 
vertebra  in  the  neck  is  at  least  as  long  as  six  in 
the  back,  so  that  the  animal  has  the  greater  part 
of  its  length  in  the  head  and  neck,  although  the 
neck  includes  so  few  vertebrae.  Nearly  all  the  teeth 
— which  are  few  in  number,  short  and  broad,  not 
exceeding  a  dozen  in  either  jaw — are  limited  to  the 
front  part  of  the  beak,  and  do  not  extend  anywhere 
near  the  nasal  vacuity.  This  is  not  the  case  with  all. 

In  the  species  named  P.  Kochi,  which  I  have  re- 
garded as  the  type  of  a  distinct  genus,  there  are 
large  teeth  in  the  front  of  the  jaw  corresponding  to 
those  of  Pterodactylus,  and  behind  these  a  smaller 
series  of  teeth  extending  back  under  the  nostril, 
which  approaches  close  to  the  orbit  of  the  eye, 
without  any  indication  of  a  separate  antorbital 
vacuity.  On  those  characters  the  genus  Diope- 
cephalus  was  defined.  It  is  closely  allied  to  Ptero- 
dactylus ;  both  agree  in  having  the  ilium  prolonged 
forward  more  than  twice  as  far  as  it  is  carried  back- 
ward, the  anterior  process  covering  about  half  a 
dozen  vertebrae,  as  in  Pterodactylus  longirostris.  A 
great  many  different  types  have  been  referred  to 
Pterodactylus  Kochi,  and  it  is  probable  that  they 
may  eventually  be  distinguished  from  each  other. 
The  species  in  which  the  upper  borders  of  the  orbits 
approximate  could  be  separated  from  those  in  which 
the  frontal  interspace  is  wider. 

It  is  a  remarkable  feature  in  these  animals  that 


p   * 

I  I 


1 

s  1 


FROM  MIDDLE  SECONDARY  ROCKS    169 

the  middle  bones  of  the  foot,  termed  instep  bones 
or  metatarsals,  are  usually  close  together,  so  that 
the  toes  diverge  from  a  narrow  breadth,  as  in  P. 
longirostris,  P.  Kocht,  and  other  forms ;  but  there 
also  appear  to  be  splay-footed  groups  of  Ptero- 
dactyles  like  the  species  which  have  been  named 
P.  elegans  and  P.  micronyx,  in  which  the  metatarsus 
widens  out  so  that  the  bones  of  the  toes  do  not 
diverge,  and  that  condition  characterises  the  Pteno- 
dracon  (Pterodactylus  brevirostris),  to  which  genus 
these  species  may  possibly  be  referred.  Nearly  all 
who  have  studied  these  animals  regard  the  singu- 
larly short-nosed  species  P.  brevirostris  as  forming  a 
separate  genus.  For  that  genus  Sommerring's  de- 
scriptive name  Ornithocephalus,  which  he  used  for 
Pterodactyles  generally,  might  perhaps  have  been 
retained.  But  the  name  Ptenodracon,  suggested  by 
Mr.  Lydekker,  has  been  used  for  these  types. 

Some  of  the  largest  specimens  preserved  at  Stutt- 
gart and  Tubingen  have  been  named  Pterodactylus 
suevicus  and  P.  Fraasii.  They  do  not  approach  the 
species  P.  grandis  in  size,  so  far  as  can  be  judged 
from  the  fragmentary  remains  figured  by  Von  Meyer; 
for  what  appears  to  be  the  third  phalange  of  the 
wing  finger  is  7^  inches  long,  while  in  these  species 
it  is  less  than  half  that  length,  indicating  an  enor- 
mous development  of  wing,  relatively  to  the  length 
of  the  hind  limb,  which  would  probably  refer  the 
species  to  another  genus.  Pterodactylus  suevicus 
differs  from  the  typical  Pterodactyles  in  having  a 
rounded,  flattened  under  surface  to  the  lower  jaw, 
instead  of  the  common  condition  of  a  sharp  keel 
in  the  region  of  the  symphysis.  The  beak  also  seems 
flattened  and  swan-like,  and  the  teeth  are  limited  to 


1 70  DRAGONS   OF   THE   AIR 

the  front  of  the  jaw.  There  appear  to  be  some 
indications  of  small  nostrils,  which  look  upward  like 
the  nostrils  of  Rhamphorhynchus,  but  this  may  be 
a  deceptive  appearance,  and  the  nostrils  are  large 
lateral  vacuities,  which  are  in  the  position  of  ant- 
orbital  vacuities,  so  that  there  would  appear  to  be 
only  two  vacuities  in  the  side  of  the  head  in  these 


\ 

J 


FIG.   62.       CYCNORHAMPHUS  SUEV1CUS 
Skeleton  restored  from  the  bones  in  Fig.  60 

animals.  The  distinctive  character  of  the  skeleton  in 
this  genus  is  found  in  the  extraordinary  length 
of  the  metacarpus  and  in  the  complete  ossification 
of  the  smaller  metacarpal  bones  throughout  their 
length.  The  metacarpal  bones  are  much  longer  than 
the  bones  of  the  fore-arm,  and  about  twice  the  length 
of  the  humerus.  The  first  wing  phalange  is  much 


FIG.  63.      RESTORATION'   OK    SKELETON   CYCNORHAMI'HUS   FRAASI 
SHOWING  THE   LIMBS  ON   THE  RIGHT  SIDE 
From  a  sftcintfn  in  the  Museum  at  Stuttgart 


KIG.   64.      CYCN-ORHAMPHUS   FRAASl 
RESTORATION    OF    THE   FORM    OF    THE    BODY 


FROM   MIDDLE  SECONDARY  ROCKS    171 

longer  than  the  others,  which  successively  and  rapidly 
diminish  in  length,  so  that  the  third  is  half  the  length 
of  the  first.  There  are  differences  in  the  pelvis ;  for 
the  anterior  process  of  the  ilium  is  very  short,  in  com- 
parison with  its  length  in  the  genus  Pterodactylus. 
And  the  long  stalk  of  the  prepubic  bone  with  its  great 
hammer-headed  expansion  transversely  in  front  gives 
those  bones  a  character  unlike  other  genera,  so  that 
Cycnorhamphus  ranks  as  a  good  genus,  easily  distin- 
guished from  Cuvier's  type,  in  which  the  four  bones 
of  the  wing  are  more  equal  in  length,  and  the  last  is 
more  than  half  the  length  of  the  first ;  while  the 
metacarpus  in  that  genus  is  only  a  little  longer  than 
the  humerus,  and  much  shorter  than  the  ulna.  The 
Pterodactylus  suevicus  has  the  neck  vertebrae  flat  on 
the  under  side,  and  relatively  short  as  compared 
with  the  more  slender  and  narrower  vertebrae  of 
P.  FraasiL 


CHAPTER   XV 

ORNITHOSAURS  FROM  THE  UPPER 
SECONDARY  ROCKS 

WHEN  staying  at  Swanage,  in  Dorsetshire, many 
years  ago,  I  had  the  rare  good  fortune  to  ob- 
tain from  the  Purbeck  Beds  the  jaw  of  a  Pterodactyle, 
which  had  much  in  common  in  plan  with  the  Cycno- 
rhamphus  Fraasii  from  the  Lithographic  Slate,  which 
is  preserved  at  Stuttgart.  The  tooth-bearing  part  of 
this  lower  jaw  is  8  inches  long  as  preserved,  extending 
back  3  inches  beyond  the  symphysis  portion  in  which 
the  two  sides  are  blended  together.  It  is  different 
from  Professor  Fraas's  specimen  in  having  the  teeth 
carried  much  further  back,  and  in  the  animal  being 
nearly  twice  as  large.  This  fragment  of  the  jaw  is 
little  more  than  I  foot  long,  which  is  probably  less 
than  half  its  original  length.  A  vertebra  nearly 
5  inches  long,  which  is  more  than  twice  the  length 
of  the  longest  neck  bones  in  the  Stuttgart  fossil,  is 
the  only  indication  of  the  vertebral  column.  Pro- 
fessor Owen  described  a  wing  finger  bone  from  these 
Purbeck  Beds,  which  is  nearly  I  foot  long.  He  terms 
it  the  second  of  the  finger.  It  may  be  the  third,  and 
on  the  hypothesis  that  the  animal  had  the  proportions 
of  the  Solenhofen  fossil  just  referred  to,  the  first  wing 
172 


FROM  UPPER  SECONDARY  ROCKS  173 

finger  bone  of  the  English  Purbeck  Pterodactyle 
would  have  exceeded  2  feet  in  length,  and  would 
give  a  length  for  the  wing  finger  of  about  5  feet 
3  inches.  For  this  animal  the  name  Doratorhynchus 
was  suggested,  but  at  present  I  am  unable  to  dis- 


FIG.   65.      THE   LONGEST   KNOWN   NECK   VERTEBRA 
From  the  Purbeck  Beds  of  Swanage.    (Half  natural  size) 

tinguish  it  satisfactorily  from  Cycnorhamphus,  which 
it  resembles  in  the  forms  both  of  the  neck  bones  and 
of  the  jaw.  Very  small  Pterodactyles  are  also  found 
in  the  English  Purbeck  strata,  but  the  remains  are 
few,  and  scattered,  like  these  larger  bones. 

ORNITHODESMUS   LATIDENS 

The  Wealden  strata  being  shallow,  fresh -water 
deposits  might  have  been  expected  to  supply  better 
knowledge  of  Pterodactyles  than  has  hitherto  been 


Back 

FIG.  66.       CERVICAL   VERTEBRA   OF   ORNITHODESMUS 
From  the  Wealden  Beds  of  the  Isle  of  Wight 


174  DRAGONS   OF   THE  AIR 

available.  Jaws  of  Ornithocheirus  sagittirostris  have 
been  found  in  the  beds  at  Hastings,  and  in  other 
parts  of  Sussex.  Some  fragments  are  as  large  as 
anything  known.  The  best-preserved  remains  have 
come  from  the  Isle  of  Wight,  and  were  rewards  to 
the  enthusiastic  search  of  the  Rev.  W.  Fox,  of  Brixton. 
In  the  principal  specimen  the  teeth  were  short  and 
wide,  the  head  large  and  deep  with  large  vacuities, 
but  the  small  brain  case  of  that  skull  is  bird-like. 
The  neck  bones  are  2.\  inches  long.  In  the  upper 
part  of  the  back  the  bones  are  united  together  by 
anchylosis,  so  that  they  form  a  structure  in  the  back 
like  a  sacrum,  which  does  not  give  attachment  to  the 
scapula,  as  in  some  Pterodactyles  from  the  Chalk,  but 
the  bones  are  simply  blended,  as  in  the  frigate-bird, 
allied  to  Pelicans  and  Cormorants.  And  then  after  a 
few  free  vertebrae  in  the  lower  part  of  the  back,  succeeds 
the  long  sacrum,  formed  in  the  usual  way,  of  many 
vertebrae.  I  described  a  sacrum  of  this  type  from  the 
Wealden  Beds,  under  the  name  Ornithodesmus,  refer- 
able to  another  species,  which  in  many  respects  was 
so  like  the  sacrum  of  a  Bird  that  I  could  not  at  the 
time  separate  it  from  the  bird  type.  This  genus  has 
a  sternum  with  a  strong  deep  keel,  and  the  articula- 
tion for  the  coracoid  bones  placed  at  the  back  of  the 
keel  in  the  usual  way,  but  with  a  relation  to  each 
other  seen  in  no  genus  hitherto  known,  for  the 
articular  surfaces  are  wedge-shaped  instead  of  being 
ovate ;  and  instead  of  being  side  by  side,  they  ob- 
liquely overlap,  practically  as  in  wading  birds  like  the 
Heron.  I  have  never  seen  any  Pterodactyle  teeth  so 
flattened  and  shaped  like  the  end  of  a  lancet ;  and 
from  this  character  the  form  was  known  between 
Mr.  Fox  and  his  friends  as  "  latidens."  The  name 


FROM  UPPER  SECONDARY  ROCKS     175 

Ornithodesmus  is  as  descriptive  of  the  sternum  as  of 
the  vertebral  column.  The  wing  bones,  as  far  as 
they  are  preserved,  have  the  relatively  great  strength 


FIG.  67.       STERNUM    OF   ORNITHODESMUS 

Showing  the  overlapping  facets  for  the  coracoid  bones  (shaded) 

behind  the  median  keel 

in  the  fore  limb  which  is  found  in  many  of  the  Ptero- 
dactyles  of  the  Cretaceous  period,  and  are  quite  as 
large  as  the  largest  from  the  Cambridge  Greensand. 


FIG.  68.  FRONT  OF  THE  KEEL  OF  THE  STERNUM  OF 

ORNITHODESMUS  LA  T1DSKS 
Showing  also  the  articulation  for  the  coracoid  bone 

In   the  Sussex  species   named  P.  sagittirostris  the 
lower  jaw  articulation  was  inches  wide. 

A  few  Pterodactyles'  bones  have  been  discovered 


1 76  DRAGONS    OF   THE   AIR 

in  the  Neocomian  sands  of  England  and  Germany, 
and  other  larger  bones  occur  in  the  Gault  of  Folke- 
stone and  the  north  of  France ;  but  never  in  such 
association  as  to  throw  light  on  the  aspect  of  the 
skeleton. 

ORNITHOCHEIRUS 

Within  my  own  memory  Pterodactyle  remains 
were  equally  rare  from  the  Cambridge  Greensand. 
The  late  Professor  Owen  in  one  of  his  public  lectures 
produced  the  first  few  fragments  received  from 
Cambridge,  and  with  a  knowledge  which  in  its 
scientific  method  seemed  to  border  on  the  power  of 
creation,  produced  again  the  missing  parts,  so  that 
the  bones  told  their  story,  which  the  work  of  waves 
and  mineral  changes  in  the  rock  had  partly  ob- 
literated. Subsequently  good  fortune  gave  me  the 
opportunity  during  ten  years  to  help  my  University 
in  the  acquisition  and  arrangement  of  the  finest 
collection  of  remains  of  these  animals  in  Europe. 
Out  of  an  area  of  a  few  acres,  during  a  year  or  two, 
came  the  thousand  bones  of  Ornithosaurs,  mostly 
associated  sets  of  remains,  each  a  part  of  a  separate 
skeleton,  described  in  my  published  catalogues,  as 
well  as  the  best  of  those  at  York  and  in  the  British 
Museum  and  other  collections  in  London. 

The  deposit  which  yields  them,  named  Cambridge 
Greensand,  may  or  may  not  represent  a  long  period 
of  time  in  its  single  foot  of  thickness  ;  but  the  abund- 
ance of  fossils,  obtained  whenever  the  workmen  were 
adequately  remunerated  for  preserving  them,  would 
suggest  that  the  Pterodactyles  might  have  lived 
like  sea-birds  or  in  colonies  like  the  Penguins,  if 
it  were  not  that  the  number  of  examples  of  each 
species  found  is  always  small,  and  the  many  variations 


FROM  UPPER  SECONDARY  ROCKS  177 

of  structure  suggested  rather  that  the  individuals 
represent  the  life  of  many  lands.  The  collections  of 
remains  are  mostly  from  villages  in  the  immediate 
vicinity  of  Cambridge,  such  as  Chesterton,  Hunting- 
don Road,  Coldham  Common,  Haslingfield,  Barton, 
Shillington,  Ditton,  Granchester,  Harston,  Barring- 
ton,  stretching  south  to  Ashwell  in  Bedfordshire  on 
the  one  hand,  as  well  as  further  north  by  Horning- 
sea  into  the  fens.  Each  appears  to  be  the  associated 
bones  of  a  single  individual.  The  remains  mostly 
belong  to  comparatively  large  animals.  Some  were 
small,  though  none  have  been  found  so  diminutive 


FIG.  69.      RESTORATION  OF  THE  SKULL  OF  ORNITHOCHEIRUS 

The  parts  left  white  are  in  the  Geological  Museum  at  Cambridge.     The  shaded 

parts  have  not  been  found.     The  two  holes  are  the  eye  and  the  nostril 

(From  the  Cambridge  Greensand) 

as  the  smallest  from  the  Solenhofen  Slate.  The 
largest  specimens  with  long  jaws  appear  to  have 
had  the  head  measuring  not  more  than  eighteen 
inches  in  length,  which  is  less  than  half  the  size  of 
the  great  toothless  Pterodactyles  from  Kansas. 

The  Cambridge  specimens  manifestly  belong  to  at 
least  three  genera.  Something  may  be  said  of  the 
characters  of  the  large  animals  which  are  included  in 
the  genus  Ornithocheirus.  These  fossils  have  many 
points  of  structure  in  common  with  the  great 
American  toothless  forms  which  are  of  similar  geo- 
logical age.  The  skull  is  remarkable  for  having  the 


i;8  DRAGONS   OF   THE   AIR 

back  of  the  head  prolonged  in  a  compressed  median 
crest,  which  rose  above  the  brain  case,  and  extended 
upward  and  over  the  neck  vertebrae,  so  as  to  indicate 
a  muscular  power  not  otherwise  shown  in  the  group. 
For  about  three  inches  behind  the  brain  this  wedge 
of  bone  rested  on  the  vertebrae,  and  probably  over- 
lapped the  first  three  neural  arches  in  the  neck. 

Another  feature  of  some  interest  is  the  expansion 
of  the  bone  which  comes  below  the  eye.  In  Birds 
this  malar  or  cheek  bone  is  a  slender  rod,  but  in 
these  Pterodactyles  it  is  a  vertical  plate,  which  is 
blended  with  the  bone  named  the  quadrate  bone, 
which  makes  the  articulation  with  the  lower  jaw  in 
all  oviparous  animals. 

The  beak  varies  greatly  in  length  and  in  form, 
though  it  is  never  quite  so  pointed  as  in  the  American 
genus,  for  there  is  always  a  little  truncation  in  front, 
when  teeth  are  seen  projecting  forward  from  a  posi- 
tion somewhat  above  the  palate ;  the  snout  is  often 
massive  and  sometimes  club-shaped.  Except  for  these 
variations  of  shape  in  the  compressed  snout,  which  is 
characterised  by  a  ridge  in  the  middle  of  the  palate, 
and  a  corresponding  groove  in  the  lower  jaw,  and 
the  teeth,  there  is  little  to  distinguish  what  is  known 
of  the  skull  in  its  largest  English  Greensand  fossils 
from  the  skull  remains  which  abound  in  the  Chalk 
of  Kansas. 

This  English  genus  Ornithocheirus,  represented  by 
a  great  number  of  species,  had  the  neural  arch  of 
the  neck  bones  expanded  transversely  over  the  body 
of  the  vertebra  in  a  way  that  characterises  many 
birds  with  powerful  necks,  and  is  seen  in  a  few 
Pterodactyles  from  Solenhofen. 

It  is  difficult  to  resist  the  conclusion  that  the  neck 


FROM  UPPER  SECONDARY  ROCKS  179 

vertebrae  were  not  usually  more  than  twice  to  three 
times  as  long  as  those  of  the  back,  and  it  would 
appear  that  the  caudal  vertebras  in  the  English 
Cretaceous  types  were  comparatively  large,  and 
about  twice  as  long  as  the  dorsal  vertebras.  Unless 
there  has  been  a  singular  succession  of  accidents  in 
the  association  of  these  vertebrae  with  the  other  re- 
mains, Ornithocheirus  had  a  tail  of  moderate  length, 
formed  of  a  few  vertebrae  as  long  as  those  of  the 
neck,  though  more  slender,  quite  unlike  the  tail  in 
either  the  long-tailed  or  short-tailed  groups  of  Solen- 


FIG.  7O.      CERVICAL  VERTEBRA,  ORNITHOCHEIRUS 
Under  side,  half  natural  size.    (Cambridge  Greensand) 

hofen  Pterodactyles,  and  longer  than  in  the  tooth- 
less Pterodactyles  of  America. 

The  singular  articulation  for  the  humerus  at  the 
truncated  extremity  of  the  coracoid  bone  is  a 
character  of  this  group,  as  is  the  articulation  of  the 
scapulae  with  the  neural  arches  of  the  dorsal  vertebrae, 
at  right  angles  to  them  (p.  115),  instead  of  running 
over  the  ribs  as  in  Birds  and  as  in  other  Pterodactyles. 

The  smaller  Pterodactyles  have  their  jaws  less  com- 
pressed from  side  to  side.  The  upper  arm  bone,  the 
humerus,  instead  of  being  truncated  at  its  lower  end 
as  in  Ornithocheirus,  is  divided  into  two  or  three 


i8o  DRAGONS   OF   THE   AIR 

rounded  articular  surfaces.  That  for  the  radius,  the 
bone  which  carries  the  wrist,  is  a  distinct  and  oblique 
rounded  facet,  while  the  ulna  has  a  rounded  and 
pulley-like  articulation  on  which  the  hand  may  rotate. 
These  differences  are  probably  associated  with  an 
absence  of  the  remarkable  mode  of  union  of  the 
scapulae  with  the  dorsal  vertebrae.  But  I  have 
hesitated  to  give  different  names  to  these  smaller 
genera  because  no  example  of  scapula  has  come 
under  my  notice  which  is  not  truncated  at  the  free 
end.  I  do  not  think  this  European  type  can  be 


FIG.  71.     UPPER  AND  LOWER  JAWS  OF  AN  ENGLISH  PTERODACTYLE 
FROM  THE  CHALK,  AS  PRESERVED 

the  Nyctodactylus  of  Professor  Marsh,  in  which 
sutures  appear  to  be  persistent  between  the  bodies 
of  the  vertebrae  and  their  arches,  because  no  examples 
have  been  found  at  Cambridge  with  the  neural  arches 
separated,  although  the  scapula  is  frequently  separated 
from  the  coracoid  in  large  animals. 

ORNITHOSTOMA 

The  most  interesting  of  all  the  English  Ptero- 
dactyle  remains  is  the  small  fragment  of  jaw  figured  by 
Sir  Richard  Owen  in  1859,  which  is  a  little  more  than 


FROM  UPPER  SECONDARY  ROCKS     181 

two  inches  long  and  an  inch  wide,  distinguished  by  a 
concave  palate  with  smooth  rounded  margins  to  the 
jaws  and  a  rounded  ridge  to  the  beak.  It  is  the  only 
satisfactory  fragment  of  the  animal  which  has  been 
figured,  and  indicates  a  genus  of  toothless  Pterodac- 
tyles,  for  which  the  name  Ornithostoma  was  first  used 
in  1871.  After  some  years  Professor  Marsh  found 
toothless  Pterodactyles  in  Kansas,  and  indicated 
several  species.  There  are  remains  to  the  number  of 
six  hundred  specimens  of  these  American  animals  in 


Transverse  section 
of  the  jaw  of 
Ornithostoma 


Palate  of 
Ornithostoma 


FIG.  72.      THE   I'ALATE  OF   THE   ENGLISH   TOOTHLESS 
PTERODACTYLE,   ORNITHOSTOMA 

the  Yale  Museum  alone ;  but  very  little  was  known  01 
them  till  Professor  Williston,  of  Lawrence,  in  Kansas, 
described  the  specimens  from  the  Kansas  University 
Museum,  when  it  became  evident  that  the  bones  of 
the  skeleton  are  mostly  formed  on  the  same  plan 
as  those  of  the  Cambridge  Greensand  genus,  Ornitho- 
cheirus.  They  are  not  quite  identical.  Professor 
Williston  adopts  for  them  the  name  Ornithostoma, 
in  preference  to  Pteranodon  which  Marsh  had 


182 


DRAGONS   OF  THE   AIR 


suggested.  Both  animals  have  the  dagger-shaped  form 
of  jaw,  with  corresponding  height  and  breadth  of  the 
palate.  The  same  flattened  sides  to  the  snout,  con- 
verging upwards  to  a  rounded  ridge,  the  same  com- 
pressed rounded  margin  to  the  jaw,  which  represents 
the  border  in  which  teeth  are  usually  implanted,  and 
in  both  the  palate  has  the  same  smooth  character 


Skull  seen 
from  above 


Palate  and  back 
of  head  seen 
from  below 


FIG.  73.      TYPES   OF   THE   AMERICAN   TOOTHLESS 
PTERODACTYLS,  ORNITHOSTOMA 

Named  by  Marsh,  Pteranodon 

forming  a  single  wide  concave  channel.  Years  pre- 
viously I  had  the  pleasure  of  showing  to  Professor 
Marsh  the  remarkable  characters  of  the  jaw,  shoulder- 
girdle  bones,  and  scapulae  in  the  Greensand  Ptero- 
dactyles  while  the  American  fossils  were  still  undis- 
covered. I  subsequently  made  the  restoration  of  the 
shoulder-girdle  (p.  115).  Professor  Williston  states  to 


FROM  UPPER  SECONDARY  ROCKS  183 

me  that  the  shoulder-girdle  bones  in  American  ex- 
amples of  Ornithostoma  have  a  close  resemblance  to 
those  of  Ornithocheirus  figured  in  1891,  as  is  evident 
from  remains  now  shown  in  the  British  Museum.  It 
appears  that  the  Kansas  bones  are  almost  invariably 
crushed  flat,  so  that  their  articular  ends  are  distorted. 
The  neck  vertebrae  are  relatively  stout  as  in  Ornitho- 
cheirus. The  hip-girdle  of  the  American  Ornitho- 
stoma can  be  closely  paralleled  in  some  English 
specimens  of  Ornithocheirus,  though  each  prepubic 
bone  is  triangular  in  the  American  fossils  as  in 
P.  rhamphastinus.  They  are  united  into  a  transverse 


FIG.  74.      RESTORATION   OF  THE  SKELETON   OF 

ORNITHOSTOMA   INGEKS  (MARSH) 

From  the  Niobrara  Cretaceous  of  Western  Kansas.     Made  by  Professor  Williston. 

The  original  has  a  spread  of  wing  of  about  19  feet  4  inches.     Fragments  of 

larger  individuals  are  preserved  at  Munich 

bar  as  in  Rhamphorhynchus,  unknown  in  the  English 
fossils.  The  femur  has  the  same  shape  as  in  Orni- 
thocheirus ;  and  the  long  tibia  terminates  in  a  pulley. 
There  is  no  fibula.  The  sternum  in  both  has  a 
manubrium,  or  thick  keel  mass,  prolonged  in  front 
of  its  articular  facets  for  the  coracoid  bones,  which 
are  well  separated  from  each  other.  Four  ribs 
articulate  with  its  straight  sides.  The  animal  has 
four  toes  and  the  fifth  is  rudimentary;  there  are  no 
claws  to  the  first  and  second. 


1 84  '  DRAGONS   OF  THE   AIR 

In  the  restoration  which  Professor  Williston  has 
made  the  wing  metacarpal  is  long,  and  in  the  shortest 
specimen  measures  I  foot  7  inches,  and  in  the  longest 
i  foot  8  inches.  This  is  exactly  equal  to  the  length 
of  the  first  phalange  of  the  wing  finger.  The  second 
wing  finger  bone  is  3  inches  shorter,  the  third  is  little 
more  than  half  the  length  of  the  first,  while  the  fourth 
is  only  6f  inches  long,  showing  a  rapid  shortening  of 
the  bones,  a  condition  which  may  have  character- 
ised all  the  Cretaceous  Pterodactyles.  The  short 
humerus,  about  I  foot  long,  and  the  fore-arm,  which 
is  scarcely  longer,  are  also  characteristic  proportions 
of  Ornithostoma  or  Pteranodon,  as  known  from  the 
American  specimens.  Professor  Williston  gives  no 
details  of  the  remarkable  tail,  beyond  saying  that  the 
tail  is  small  and  short,  and  that  the  vertebrae  are  flat 
at  the  ends,  without  transverse  processes.  In  the  re- 
storation the  tail  is  shorter  than  in  the  short-tailed 
species  from  the  Lithographic  Slate,  and  unlike  the 
tail  in  Ornithocheirus. 

This  is  the  succession  of  Pterodactyles  in  geolo- 
gical time.  Their  history  is  like  that  of  the  human 
race.  In  the  most  ancient  nations  man's  life  comes 
upon  us  already  fully  organised.  The  Pterodactyles 
begin,  so  far  as  isolated  bones  are  concerned,  in  the 
Rhaetic  strata;  perhaps  in  the  Muschelkalk  or  middle 
division  of  the  Trias.  And  from  the  beginning 
of  the  Secondary  time  they  live  on  with  but  little 
diversity  in  important  and  characteristic  structures, 
and  so  far  as  habit  goes,  the  great  Pterodactyles 
of  the  Upper  Chalk  of  England  cannot  be  said  to 
be  more  highly  organised  than  the  earlier  stiff-tailed 
genera  of  the  Lias  or  the  Oolites.  There  is  nothing 


FROM  UPPER  SECONDARY  ROCKS  185 

like  evolution.  No  modification  such  as  that  which 
derives  the  one-toed  horse  or  the  two-toed  ox  from 
ancestors  with  a  larger  number  of  digits.  On  the 
other  hand,  there  is  little,  if  any,  evidence  of  de- 
generation. The  later  Pterodactyles  do  not  appear 
to  have  lost  much,  although  the  tail  in  some  of  the 
Solenhofen  genera  may  be  degenerate  when  com- 
pared with  the  long  tail  of  Dimorphodon  ;  but  the 
short-tailed  types  are  found  side  by  side  with  the 
long-tailed  Rhamphorhynchus.  The  absence  of  teeth 
may  be  regarded  as  degeneration,  for  they  have 
presumably  become  lost,  in  the  same  way  that  Birds 
now  existing  have  lost  the  teeth  which  characterised 
the  fossil  birds — Ichthyornis  of  the  American  Green- 
sand,  and  Archaeopteryx  of  the  Upper  Oolites  of 
Bavaria.  But  just  as  some  of  the  earlier  Pterodac- 
tyles have  no  teeth  at  the  extremity  of  the  jaw,  such 
as  Dorygnathus  and  Rhamphorhynchus,  so  the  loss 
of  teeth  may  have  extended  backward  till  the  jaws 
became  toothless.  The  specimens  hitherto  known 
give  no  evidence  of  such  a  change  being  in  progress. 
But  just  as  the  divison  of  Mammals  termed  Edentata 
usually  wants  only  the  teeth  which  characterise  the 
front  of  the  jaw,  yet  others,  like  the  Great  Ant-eater 
of  South  America  named  Myrmecophaga,  have  the 
jaws  as  free  from  teeth  as  the  toothless  Pterodactyles 
or  living  Birds,  and  show  that  in  that  order  the  teeth 
have  no  value  in  separating  these  animals  into  sub- 
ordinate groups  any  more  than  they  have  among  the 
Monotremata,  where  one  type  has  teeth  and  the  other 
is  toothless. 


1 86 


DRAGONS   OF   THE   AIR 


The  following  table  gives  a  summary  of  the  Geo- 
logical History  and  succession  in  the  Secondary 
Rocks  of  the  principal  genera  of  Flying  Reptiles. 


<AMES   OF   THE   GENERA. 


GEOLOGICAL   FORMATIONS. 


British  and  European. 


North  American. 


Upper  Chalk 

Lower  Chalk 
Upper  Greensand 
Gault 

Lower  Greensand 
Wealden  . 
Purbeck   . 


Portland  . 

Kimeridge     Clay     and 

Solenhofen  Slate 
Coralline  Oolite   . 
Oxford  Clay 


Great   Oolite   and 
Stonesfield  Slate 
Inferior  Oolite 


Upper  Lias 
Lower  Lias 


Rhretic     . 
Muschelkalk 


|  -I  Ornithocheirus 
V  Ornithostoma 


Ornithodesmus 
Doratorhynchus 

f  Pterodactylus 
Ptenodracon 
Cycnorhamphus 

i  Diopecephalus 
Rhamphorhynchus 

(Scaphognathus 

Rhamphocephalus 

/  Campylognathus 
\  Dorygnathus 
Dimorphodon 

bones 
?  bones 


"j  Ornithostoma 
j-         (Pteranodoit) 
J  Nyctodactylus 


CHAPTER   XVI 

CLASSIFICATION    OF   THE 
ORNITHOSAURIA 

WHEN  an  attempt  is  made  to  determine  the 
place  in  nature  of  an  extinct  group  of  animals 
and  the  relation  to  each  other  of  the  different  types 
included  within  its  limits,  so  as  to  express  those  facts 
in  a  classification,  attention  is  directed  in  the  first 
place  to  characters  which  are  constant,  and  persist 
through  the  whole  of  its  constituent  genera.  We 
endeavour  to  find  the  structural  parts  of  the  skeleton 
which  are  not  affected  by  variation  in  the  dentition, 
or  the  proportions  of  the  extremities,  or  length  of 
the  tail,  which  may  define  families  or  genera,  or 
species. 

It  has  already  been  shown  that  while  in  many 
ways  the  Ornithosaurian  animals  are  like  Birds,  they 
have  also  important  resemblances  to  Reptiles.  They 
are  often  named  Pterosauria.  The  wing  finger  gives 
a  distinctive  character  which  is  found  in  neither  one 
class  of  existing  animals  nor  the  other,  and  is  common 
to  all  the  Pterodactyles  at  present  known.  They  have 
been  named  Ornithosauria  as  a  distinct  minor  division 
of  back-boned  animals,  which  may  be  regarded  as 
neither  Reptiles  nor  Birds  in  the  sense  in  which  those 
187 


1 86  DRAGONS   OF  THE   AIR 

terms  are  used  to  define  a  Lizard  or  Ostrich  among 
animals  which  still  exist.  It  is  not  so  much  that  they 
mark  a  transition  from  Reptile  to  Bird,  as  that  they 
are  a  group  which  is  parallel  to  Birds,  and  more 
manifestly  holds  an  intermediate  place  than  Birds  do 
between  Reptiles  and  Mammals.  In  plan  of  structure 
Bird  and  Reptile  have  more  in  common  than  was 
at  one  time  suspected.  The  late  Professor  Huxley 
went  so  far  as  to  generalise  on  those  coincidences 
in  parts  of  the  skeleton,  and  united  Birds  and  Reptiles 
into  one  group,  which  he  named  Sauropsida,  to  ex- 
press the  coincidences  of  structure  between  the  Lizard 
and  the  Bird  tribes.  The  idea  is  of  more  value  than 
the  term  in  which  it  is  expressed,  because  Reptiles 
are  not,  as  we  have  seen,  a  group  of  animals  which 
can  be  defined  by  any  set  of  characters  as  compre- 
hensive as  those  which  express  the  distinctive  features 
of  Birds.  From  the  anatomist's  point  of  view  Birds 
are  a  smaller  group,  and  while  some  Reptiles  have 
affinity  with  them,  it  is  rather  the  extinct  than  the 
living  groups  which  indicate  that  relation.  Other 
Reptiles  have  affinities  of  a  more  marked  kind  with 
Mammals,  and  there  are  points  in  the  Ornithosaurian 
skeleton  which  are  distinctly  Mammalian.  So  that 
when  the  Monotreme  Mammals  are  united  with 
South  African  reptiles  known  as  Theriodontia,  which 
resemble  them,  in  a  group  termed  Theropsida  to 
express  their  mammalian  resemblances,  it  is  evident 
that  there  is  no  one  continuous  chain  of  life  or  grada- 
tion in  complexity  of  structure  of  animals. 

We  have  to  determine  whether  the  Ornithosauria  in- 
cline towards  the  Sauropsidan  or  Bird-Reptile  alliance, 
or  to  the  Mammal-Reptile  or  Theropsidan  alliance. 
There  can  be  no  doubt  that  the  predominant  ten- 


ORNITHOSAURIA  CLASSIFICATION    189 

dency  is  to  the  former,  with  a  minor  affinity  towards 
the  latter. 

The  Ornithosauria  are  one  of  a  series  of  groups 
of  animals,  living  and  extinct,  which  have  been 
combined  in  an  alliance  named  the  Ornithomorpha. 
That  group  includes  at  least  five  great  divisions 
of  animals,  which  circle  about  birds,  known  as 
Ornithosauria,  Crocodilia,  Saurischia,  Aves,  Ornith- 
ischia,  and  Aristosuchia.  Their  relations  to  each  other 
are  not  evident  in  an  enumeration,  but  may  be  shown 
in  some  degree  in  a  diagram  (see  p.  190). 

THE    ORNITHOMORPHA 

The  Ornithomorpha  arranged  in  this  way  show 
that  the  three  middle  groups — carnivorous  Saurischia, 
Aristosuchia,  herbivorous  Ornithischia — which  are 
usually  united  as  Dinosauria,  intervene  between 
Birds  and  Ornithosaurs ;  and  that  the  Crocodilia 
and  Ornithosauria  are  parallel  groups  which  are  con- 
nected with  Birds,  by  the  group  of  Dinosaurs,  which 
resembles  Birds  most  closely. 

The  Ornithomorpha  is  only  one  of  a  series  of  large 
natural  groups  of  animals  into  which  living  and 
extinct  terrestrial  vertebrata  may  be  arranged.  And 
the  succeeding  diagram  may  contribute  to  make 
evident  the  relations  of  Ornithosauria  to  the  other 
terrestrial  vertebrata  (see  p.  191). 

Herein  it  is  seen  that  while  the  Ornithomorpha 
approach  towards  Mammalia  through  the  Ornitho- 
sauria, and  less  distinctly  through  the  Crocodilia, 
they  approach  more  directly  to  the  Sauromor- 
pha,  through  the  Plesiosaurs  and  Hatteria ;  while 
that  group  also  approaches  more  directly  to  the 
Mammals  through  the  Plesiosaurs  and  Anomodonts. 


190  DRAGONS   OF   THE   AIR 


DIAGRAM  OF  THE  AFFINITIES  OF  THE  ORDERS  OF  ANIMALS 
COMPRISED   IN  THE  ORNITHOMORPHA. 


\  / 

Ornithosauria  I  Crocodilia 


Saurischia  I  Aristosuchia  lOrnithischia 


Aves 


After  a  diagram  in  the  Philosophical  Transactions  Oj   the 
Royal  Society,   1892. 


The  Aristosuchia  is  imperfectly  known,  and  there- 
fore to  some  extent  a  provisional  group.  It  is  a 
small  group  of  animals. 


ORNITHOSAURIA  CLASSIFICATION    191 


DIAGRAM  SHOWING  THE  RELATIONS  OF  THE  ORNITHOMORPHA 
TO  THE  CHIEF  LARGE  GROUPS  OF  TERRESTRIAL  VKRTEBRATA, 
AND  THEIR  AFFINITIES  WITH  EACH  OTHER. 


Amphibia  |  Mammalia 


Cordylomorpha YSauromorpha  lOrnithomorpha 


Herpetomoppha) 


After  a  diagram  in  the  Philosophical  Transactions  of  the 
Royal  Society,   1892. 


Cordylomorpha  are  Ichthyosaurs  and  the  Laby- 
rinthodont  group.  Herpetomorpha  include  Lacer- 
tilia,  Homoeosauria,  Dolichosauria,  Chameleonoidea, 
Ophidia,  Pythonomorpha. 


192  DRAGONS   OF   THE   AIR 

The  Sauromorpha  comprises  the  groups  of  extinct 
and  living  Reptiles  named  Chelonia,  Rhynchocephala, 
Sauropterygia,  Anomodontia,  Nothosauria,  and  Pro- 
torosauria.  These  details  may  help  to  explain  the 
place  which  has  been  given  to  the  Ornithosauria  in 
the  classification  of  animals. 

Turning  to  the  Pterodactyles  themselves,  Von 
Meyer  divided  them  naturally  into  short-tailed  and 
long-tailed.  The  short-tailed  indicated  by  the  name 


Dimorphodon 
Rhamphorhynchus 
Ornithostoma  (Pteranodon) 

FIG.  75.      COMPARISON  OF  SIX  GENERA 

The  skulls  are  seen  on  the  left  side  in  the  order  of  the  names  below  them 

Pterodactylus  he  further  divided  into  long-nosed  and 
short-nosed.  The  short-nosed  genus  has  since  been 
named  Ptenodracon  (Fig.  59,  p.  167).  The  long- 
tailed  group  was  divided  into  two  types — the  Rham- 
phorhynchus of  the  Solenhofen  Slate  (Fig.  56,  p.  161) 
and  the  English  form  now  known  as  Dimorphodon 
(Fig.  52,  p.  150),  which  had  been  described  from  the 
Lias. 

The    Cretaceous    Pterodactyles    form    a    distinct 


ORNITHOSAURIA  CLASSIFICATION    193 

family.  So  that,  believing  the  tail  to  have  been  short 
in  that  group  (Fig.  58),  there  are  two  long-tailed  as 
well  as  two  short-tailed  families,  which  were  defined 
from  their  typical  genera  Pterodactylus,  Ornitho- 
cheirus,  Rhamphorhynchus,  and  Dimorphodon. 

The  differences  in  structure  which  these  animals 
present  are,  first :  the  big-headed  forms  from  the  Lias 
like  Dimorphodon,  agree  with  the  Rhamphorhynchus 
type  from  Solenhofen  in  having  a  vacuity  in  the  skull 
defined  by  bone,  placed  between  the  orbit  of  the  eye 
and  the  nostril.  With  those  characters  are  correlated 
the  comparatively  short  bones  which  correspond  to 
the  back  of  the  hand  termed  metacarpals,  and  the 
tail  is  long,  and  stiffened  down  its  length  with  ossi- 
fied tendons.  These  characters  separate  Ornithosaurs 
with  long  tails  from  those  with  short  tails. 

The  short-tailed  types  represented  by  Pterodactylus 
and  Ornithocheirus  have  no  distinct  antorbital  vacuity 
in  the  skull  defined  by  bone.  The  metacarpal  bones 
of  the  middle  hand  are  exceptionally  elongated,  and 
the  tail,  which  was  flexible  in  both,  appears  to  have 
been  short.  These  differences  in  the  skeleton  warrant 
a  primary  division  of  flying  reptiles  into  two  principal 
groups. 

The  short-tailed  group,  which  was  recognised  by 
De  Blainville  as  intermediate  between  Birds  and 
Reptiles,  may  take  the  name  Pterodactylia,  which 
he  suggested  as  a  convenient,  distinctive  name.  It 
may  probably  be  inconvenient  to  enlarge  its  signific- 
ance to  comprise  not  only  the  true  Pterodactyles 
originally  defined  as  Pterosauria,  but  the  newer 
Ornithostoma  and  Ornithocheirus  which  have  been 
grouped  as  Ornithocheiroidea. 

The  second  order,  in  which  the  wing  membrane 
o 


194  DRAGONS   OF   THE   AIR 

appears  to  have  had  a  much  greater  extent,  in  being 
carried  down  the  hind  limbs,  where  the  outermost 
digit  and  metatarsal  are  modified  for  its  support,  has 
been  named  Pterodermata,  to  include  the  types 
which  are  arranged  around  Rhamphorhynchus  and 
Dimorphodon. 

Both  these  principal  groups  admit  of  subdivision 
by  many  characters  in  the  skeleton,  the  most  remark- 
able of  which  is  afforded  by  the  pair  of  bones  carried 
in  front  of  the  pubes,  and  termed  prepubic  bones. 
In  the  Pterodactyle  family  the  bones  in  front  of  the 
pubes  are  always  separate  from  each  other,  always 
directed  forward,  and  have  a  peculiar  fan-shaped 
form  with  concave  sides  like  the  bone  which  holds  a 
similar  position  in  a  Crocodile.  In  the  Ornithocheirus 
family  the  prepubic  bones  appear  to  have  been  ori- 
ginally triangular,  but  were  afterwards  united  so  as 
to  form  a  strong  continuous  bar  which  extends  trans- 
versely across  the  abdomen  in  advance  of  the  pubic 
bones.  This  at  least  is  the  distinctive  character  in  the 
genus  Ornithostoma  according  to  Professor  Williston, 
which  in  many  ways  closely  resembles  Ornithocheirus. 

The  two  families  in  the  long-tailed  order  named 
Pterodermata  are  separated  from  each  other  by  a 
similar  difference  in  their  prepubic  bones.  In  Dimor- 
phodon those  bones  are  separate  from  each  other, 
and  remain  distinct  through  life,  meeting  in  the 
middle  line  of  the  body  in  a  wide  plate.  On  the 
other  hand,  in  Rhamphorhynchus  the  prepubic  bones, 
which  are  at  first  triangular  and  always  slender, 
become  blended  together  into  a  slight  transverse  bar, 
which  only  differs  from  that  attributed  to  Ornitho- 
stoma in  its  more  slender  bow-shaped  form. 

Thus  if  other  characters  of  the  skeleton  are  ig- 


ORNITHOSAURIA  CLASSIFICATION    195 

nored  and  a  classification  based  upon  the  structure  of 
the  pelvis  and  prepubic  bones,  there  would  be  some 


Prepubis 

FIG.    76.       LEFT   SIDE   OF   PELVIS   OF   ORNITHOSTOMA 
(After  Williston) 

ground  for  associating  the  long-tailed  Rhampho- 
rhynchus  from  the  Upper  Oolites  which  is  losing  the 
teeth  in  the  front  of  its  jaw  with  the  Cretaceous  Orni- 
thostoma,  which  has  the  teeth  completely  wanting; 
while  the  long-tailed  Dimorphodon  would  come  into 
closer  association  with  the  short-tailed  Pterodactyl  us. 
The  drum-stick  bone  or  tibia  in  Dimorphodon,  with 
its  slender  fibula,  like  that  of  a  Bird,  also  resembles 
a  Bird  in  the  rounded  and  pulley-shaped  terminal 
end  which  makes  the  joint  corresponding  to  the 
middle  of  the  ankle  bones  in  man.  The  same  con- 
dition of  a  terminal  pulley  joint  is  found  in  the 
Cretaceous  Pterodactyles.  But  in  the  true  Ptero- 
dactyles  and  in  Rhamphorhynchus  there  usually  is 
no  pulley-shaped  termination  to  the  lower  end  of 
the  drum-stick,  for  the  tarsal  bones  remain  separate 
from  each  other,  and  form  two  rows  of  ossifications, 
showing  the  same  differences  as  separate  Dinosaurs 
into  the  divisions  which  have  been  referred  to,  from 
their  Bird-like  pelvis  and  tibio-tarsus,  as  Ornithischia 
in  the  one  case,  and  Saurischia  in  the  other  from 
their  bones  being  more  like  those  of  living  Lizards. 


CHAPTER  XVII 

FAMILY    RELATIONS   OF    PTERO- 

DACTYLES   TO   ANIMALS   WHICH 

LIVED  WITH   THEM 

ENOUGH  has  been  said  of  the  general  struc- 
ture of  Pterodactyles  and  the  chief  forms  which 
they  assumed  while  the  Secondary  rocks  were  accu- 
mulating, to  convey  a  clear  idea  of  their  relations 
to  the  types  of  vertebrate  animals  which  still  survive 
on  the  earth.  We  may  be  unable  to  explain  the 
reasons  for  their  existence,  and  for  their  departure 
from  the  plan  of  organisation  of  Reptiles  and  Birds. 
But  the  evidence  has  not  been  exhausted  which  may 
elucidate  their  existence.  Sometimes,  in  problems  of 
this  kind,  which  involve  comparison  of  the  details  of 
the  skeleton  in  different  animals,  it  is  convenient  to 
imagine  the  possibility  of  changes  and  transitions 
which  are  not  yet  supported  by  the  discovery  of 
fossil  remains.  If,  for  example,  the  Pterodactyle  be 
conceived  of  as  divested  of  the  wing  finger,  which  is 
its  most  distinctive  character,  or  that  finger  is  supposed 
to  be  replaced  by  an  ordinary  digit,  like  the  three- 
clawed  digits  of  the  hand  which  we  have  regarded 
as  applied  to  the  ground,  where,  it  may  be  asked, 
would  the  animal  type  be  found  which  approximates 
196 


RELATIONS  OF  PTERODACTYLES     197 

most  closely  to  a  Pterodactyle  which  had  been  thus 
modified  ?  There  are  two  possible  replies  to  such  a 
question,  suggested  by  the  form  of  the  foot.  For 
the  old  Bird  Archaeopteryx  has  three  such  clawed 
digits,  but  no  wing  finger.  And  some  Dinosaurs  also 
have  the  hand  with  three  digits  terminating  in  claws, 
which  are  quite  comparable  to  the  clawed  digits  of 
Pterodactyles. 

The  truth  expressed  in  the  saying  that  no  man  by 
taking  thought  can  add  a  cubit  to  his  stature  is  of 
universal  application  in  the  animal  world,  in  relation 
to  the  result  upon  the  skeleton  of  the  exercise  of  a 
function  by  the  individual.  Yet  such  is  the  relation 
in  proportions  of  the  different  parts  of  the  animal  to 
the  work  which  it  performs,  so  marked  is  the  evidence 
that  growth  has  extended  in  direct  relation  to  use  of 
organs  and  active  life,  and  that  structures  have  become 
dwarfed  from  overwork,  or  have  wasted  away  from 
disuse — seen  throughout  all  vertebrate  animals,  that 
we  may  fairly  attribute  to  the  wing  finger  some  corre- 
lated influence  upon  the  proportions  of  the  animal, 
as  a  consequence  of  the  dependence  of  the  entire 
economy  upon  each  of  its  parts.  Therefore  if  an 
allied  animal  did  not  possess  a  wing  finger,  and  did 
not  fly,  it  might  not  have  developed  the  lightness  of 
bone,  or  the  length  of  limb  which  Pterodactyles 
possess. 

The  mere  expansion  of  the  parachute  membrane 
seen  in  so-called  flying  animals,  both  Mammals  and 
Reptiles,  which  are  devoid  of  wings,  is  absolutely 
without  effect  in  modifying  the  skeleton.  But  when 
in  the  Bat  a  wing  structure  is  met  with  which  may 
be  compared  to  a  gigantic  extension  of  the  web  foot 
of  the  so-called  Flying  Frog,  the  bones  of  the  fingers 


198  DRAGONS   OF   THE   AIR 

and  the  back  of  the  hand  elongate  and  extend  under 
the  stimulus  of  the  function  of  flight  in  the  same 
way  as  the  legs  elongate  in  the  more  active  hoofed 
animals,  with  the  function  of  running.  Therefore  it 
is  not  improbable  that  the  limbs  shared  to  some 
extent  in  growth  under  stimulus  of  exercise  which 
developed  the  wing  finger.  And  if  an  animal  can  be 
found  among  fossils  so  far  allied  as  to  indicate  a 
possible  representative  of  the  race  from  which  these 
Flying  Dragons  arose,  it  might  be  expected  to  be  at 
least  shorter  legged,  and  possibly  more  distinctly 
Reptilian  in  the  bones  of  the  shoulder-girdle  which 
support  the  muscles  used  in  flight.  It  may  readily 
be  understood  that  the  kinds  of  life  which  were  most 
nearly  allied  to  Pterodactyles  are  likely  to  have 
existed  upon  the  earth  with  them,  and  that  flight  was 
only  one  of  the  modes  of  progression  which  became 
developed  in  relation  to  their  conditions  of  exist- 
ence. The  principal  assemblage  of  terrestrial  animals 
available  for  such  comparison  is  the  Dinosauria.  They 
may  differ  from  Pterodactyles  as  widely  as  the  In- 
sectivora  among  Mammals  differ  from  Bats,  but  not 
in  a  more  marked  way.  Comparisons  will  show  that 
there  are  resemblances  between  the  two  extinct  groups 
which  appeal  to  both  reason  and  imagination. 

Dinosaurs  are  conveniently  divided  by  characters 
of  the  pelvis  first  into  the  order  Saurischia,  which 
includes  the  carnivorous  Megalosaurus  and  the  Cetio- 
saurus,  with  the  pelvis  on  the  Reptile  plan ;  and 
secondly  the  order  Ornithischia,  represented  by  Igua- 
nodon,  with  the  pelvis  on  the  Bird  plan.  It  may  be 
only  a  coincidence,  but  nevertheless  an  interesting 
one,  that  the  characters  of  those  two  great  groups  of 
reptiles,  which  also  extend  throughout  the  Secondary 


RELATIONS  OF  PTERODACTYLES     199 

rocks,  are  to  some  extent  paralleled  in  parts  of  the 
skeleton  of  the  two  divisions  of  Pterodactyles.  This 
may  be  illustrated  by  reference  to  the  skull,  pelvis, 
hind  limb,  and  the  pneumatic  condition  of  the  bones. 
The  Saurischian  Dinosauria  have  an  antorbital 
vacuity  in  the  side  of  the  skull  between  the  nasal 
opening  and  the  eye,  as  in  the  long-tailed  Ornitho- 
saurs  named  Pterodermata.  In  some  of  the  older 
genera  of  these  carnivorous  Dinosaurs  of  the  Trias, 


Dimorphodon 

FIG.  77.      COMPARISON   OF  THE  SKULL  OF   THE 

DINOSAUR  ANCHISAURUS   WITH   THE 

ORNITHOSAUR   DIMORPHODON 

the  lateral  vacuities  of  the  head  are  as  large  as  in 
Dimorphodon.  But  in  some  at  least  of  the  Iguano- 
dont,  or  Ornithischian  Dinosaurs,  there  is  no  ant- 
orbital  vacuity,  and  the  side  of  the  face  in  that 
respect  resembles  the  short -tailed  Pterodactylia. 
The  skull  of  a  carnivorous  Dinosaur  possesses  teeth 
which,  though  easily  distinguished  from  those  of 
Pterodactyles,  can  be  best  compared  with  them.  The 


200  DRAGONS   OF   THE   AIR 

most  striking  difference  is  in  the  fact  that  in  the 
Dinosaur  the  nostrils  are  nearly  terminal,  while  in 
the  Pterodactyle  they  are  removed  some  distance 
backward.  This  result  is  brought  about  by  growth 
taking  place,  in  the  one  case  at  the  front  margin  of 
the  maxillary  bone  so  as  to  carry  the  nostril  forward, 
and  in  the  other  case  at  the  back  margin  of  the  pre- 
maxillary  bone.  Thus  an  elongated  part  of  the  jaw 
is  extended  in  front  of  the  nostril.  Hence  there  is 
a  different  proportion  between  the  premaxillary  and 
maxillary  bones  in  the  two  groups  of  animals,  which 
corresponds  to  the  presence  of  a  beak  in  a  bird,  and 
its  absence  in  living  reptiles.  It  is  not  known  whether 
the  extremity  of  the  Pterodactyle's  beak  is  a  single 
bone,  the  intermaxillary  bone,  such  as  forms  the 
corresponding  toothless  part  of  the  jaw  in  the  South 
African  reptile  Dicynodon,  or  whether  it  is  made 
by  the  pair  of  bones  called  premaxillaries  which 
form  the  extremity  of  the  jaw  in  most  Dinosaurs. 
Too  much  importance  may  perhaps  be  attached 
to  such  differences  which  are  partly  hypothetical, 
because  the  extinct  Ichthyosaurus,  which  has  an  ex- 
ceptionally long  snout,  has  the  two  premaxillary 
bones  elongated  so  as  to  extend  backward  to  the 
nostrils.  A  similar  elongation  of  those  bones  is  seen 
in  Porpoises,  which  also  have  a  long  snout;  and  the 
bones  are  carried  back  from  the  front  of  the  head  to 
the  nostrils,  which  are  sometimes  known  as  blow- 
holes. But  the  Porpoise  has  those  premaxillary 
bones  not  so  much  in  advance  of  the  bones  which 
carry  teeth  named  maxillary,  as  placed  in  the  inter- 
space between  them.  The  nostrils,  however,  are  not 
limited  to  the  extremity  of  the  head  in  all  Dinosaurs. 
If  this  region  of  the  beak  in  Dimorphodon  be  com- 


RELATIONS  OF  PTERODACTYLES     201 

pared  with  the  corresponding  part  of  a  Dinosaur 
from  the  Permian  rocks,  or  Trias,  the  relation  of  the 
nostril  to  the  bones  forming  the  beak  may  be  better 
understood. 

In  the  sandstone  of  Elgin,  usually  named  Trias,  a 
small  Dinosaur  is  found,  which  has  been  named  Orni- 
thosuchus,  from  the  resemblance  of  its  head  to  that 
of  a  Bird.  Seen  from  above,  the  head  has  a  remark- 
able resemblance  to  the  condition  in  Rhampho- 
rhynchus,  in  the  sharp-pointed  beak  and  positions 


FIG.  78.      COMPARISON   OF   THE   SKULL  OF  THE 

DINOSAUR   ORNITHOSUCHUS   WITH   THE 

ORNITHOSAUR  DIMORPHODON 

of  the  orbits  and  other  openings.  In  side  view  the 
orbits  have  the  triangular  form  seen  in  Dimorphodon, 
and  the  preorbital  vacuities  are  large,  as  in  that  genus, 
while  the  lateral  nostrils,  which  are  smaller,  are  further 
forward  in  the  Dinosaur.  The  differences  from  Dimor- 
phodon are  in  the  articulation  for  the  jaw  being 
carried  a  little  backward,  instead  of  being  vertical  as 
in  the  Pterodactyle,  and  the  bone  in  front  of  the 
nose  is  smaller.  Notwithstanding  probable  differences 


202  DRAGONS   OF  THE   AIR 

in  the  palate,  the  approximation,  which  extends  to 
the  Crocodile-like  vacuity  in  the  lower  jaw,  is  such 
that  by  slight  modification  in  the  skull  the  differences 
would  be  substantially  obliterated  by  which  the  skull 
of  such  an  Ornithosaur  is  technically  distinguished 
from  such  a  Dinosaur. 

The  back  of  the  skull  is  clearly  seen  in  the  Whitby 
Pterodactyle,  and  its  structure  is  similar  to  the  corre- 
sponding part  of  such  Dinosaurs  as  Anchisaurus  or 
Atlantosaurus,  without  the  resemblance  quite  amount- 
ing to  identity,  but  still  far  closer  than  is  the  re- 
semblance between  the  same  region  in  the  heads  of 
Crocodiles,  Lizards,  Serpents,  Chelonians.  Few  of 
these  fossil  Dinosaur  skulls  are  available  for  com- 
parison, and  those  differ  among  themselves.  The 
coincidences  rather  suggest  a  close  collateral  relation 
than  prove  the  elaboration  of  one  type  from  the 
other.  They  may  have  had  a  common  ancestor. 

The  Trias  rocks  near  Stuttgart  have  yielded  Dino- 
saurs as  unlike  Fterodactyles  as  could  be  imagined, 
resembling  heavily  armoured  Crocodiles,  in  such  types 
as  the  genus  Belodon.  Its  jaws  are  compressed  from 
side  to  side,  as  in  many  Pterodactyles,  and  the  nostrils 
are  at  least  as  far  backward  as  in  Rhamphorhynchus. 
Belodon  has  preorbital  vacuities  and  postorbital  vacui- 
ties, but  the  orbit  of  the  eye  is  never  large,  as  in 
Pterodactyles.  It  might  not  be  worth  while  dwelling 
on  such  points  in  the  skull  if  it  were  not  that  the 
pelvis  in  Belodon  is  a  basin  formed  by  the  blending 
of  the  expanded  plates  of  the  ischium  and  the  pubis, 
into  a  sheet  of  bone  which  more  nearly  resembles 
the  same  region  in  Pterodactyles  than  does  the 
ischio-pubic  region  in  other  Dinosaurian  animals 
like  Cetiosaurus. 


RELATIONS  OF  PTERODACTYLES     203 

The  backbone  in  a  few  Dinosaurs  is  suggestive  of 
Pterodactyles.  In  such  genera  as  have  been  named 
Ccelurus  and  Calamospondylus,  in  which  the  skeleton 
is  only  partially  known,  the  neck  vertebrae  become 
elongated,  so  as  to  compare  with  the  long-necked 
Pterodactyles.  The  cervical  rib  is  often  very  similar 
to  that  type,  and  blended  with  the  vertebra,  as  in 
Pterodactyles  and  Birds.  The  early  dorsal  vertebrae 
of  Pterodactyles  might  almost  be  mistaken  for  those 
of  Dinosaurs.  The  tail  vertebrae  of  a  Pterodactyle 
are  usually  longer  than  in  long-tailed  Dinosauria. 

In  the  limbs  and  the  bony  girdles  which  support 
them  there  is  more  resemblance  between  Ptero- 
dactyles and  Dinosaurs  than  might  have  been  an- 
ticipated, considering  their  manifest  differences  in 
habit  Thus  all  Dinosaurs  have  the  hip  bone  named 
ilium  prolonged  in  front  of  the  articulation  for  the 
femur  as  well  as  behind  it,  almost  exactly  as  in 
Pterodactyles  and  Birds  (see  p.  95).  There  is  some 
difference  in  the  pubis  and  ischium  which  is  more 
conspicuous  in  form  than  in  direction  of  the  bones. 
There  is  a  Pterodactyle  imperfectly  preserved,  named 
Pterodactylus  dubius,  in  which  the  ischium  is  directed 
backward  and  the  pubis  downward,  and  the  bones 
unite  below  the  acetabular  cavity  for  the  head  of  the 
femur  to  work  in,  but  do  not  appear  to  be  otherwise 
connected.  In  Rhamphorhynchus  the  connexion 
between  these  two  thickened  bars  is  made  by  a  thin 
plate  of  bone.  In  such  a  Dinosaur  as  the  American 
carnivorous  Ceratosaurus  the  two  bars  of  the  pubis 
and  ischium  remain  separate  and  diverging,  and 
there  is  no  film  of  bone  extending  over  the  inter- 
space between  them.  The  development  of  such  a 
bony  condition  would  make  a  close  approximation 


204  DRAGONS   OF   THE   AIR 

between  the  Ornithosaurian  pelvis  and  that  of  those 
Dinosaurs  which  closely  resemble  Pterodactyles  in 
skull  and  teeth. 

Another  pelvic  character  of  some  interest  is  the 
blending  of  the  pubis  and  ischium  of  the  right  and 
left  sides  in  the  middle  line  of  the  body.  There  are 
some  genera  of  Dinosaurs  like  the  English  Aristo- 


Ceratosauru 


FIG.  79.      LEFT  SIDE  OF   PELVIS 

A  Pterodactyle  is  shown  between  a  carnivorous  Dinosaur  above  and 
a  herbivorous  Dinosaur  below 

suchus  from  the  Weald,  and  the  American  genera 
Coelurus,  Ceratosaurus,  and  others,  in  which  the 
pubic  bones,  instead  of  uniting  at  their  extremities, 
are  pinched  together  from  side  to  side,  and  unite 
down  the  lower  part  of  their  length,  terminating 
in  an  expanded  end  like  a  shoe,  which  is  seen  to  be 
a  separate  ossification,  and  probably  formed  by  a  pair 


RELATIONS  OF  PTERODACTYLES     205 

of  ossifications  joined  in  the  median  line.  This  small 
bone,  which  is  below  the  pubes,  and  in  these  animals 
becomes  blended  with  them,  we  may  regard  as  a  pair 
of  prepubic  bones  like  those  of  Pterodactyles  and 
Crocodiles,  except  that  they  have  lost  the  stalk-like 
portions,  which  in  those  animals  are  developed  to 
compensate  for  the  diminished  length  of  the  pubic 
bones.  The  prepubic  bones  may  also  be  developed 
in  Iguanodon,  in  which  a  pair  of  bones  of  similar 
form  remains  throughout  life  in  advance  of  the 
pubes,  as  in  Pterodactyles.  In  those  Dinosauria 
with  the  Bird-like  type  of  pelvis  the  pubic  bone 
is  exceptionally  developed,  sending  one  process 
backward  and  another  process  forward,  so  that 
there  is  a  great  gap  between  these  diverging  limbs 
to  the  bone.  In  the  region  behind  the  sternum  to 
which  the  ribs  were  attached,  and  in  front  of  the 
pelvis,  is  a  pair  of  bones  in  Iguanodon  shaped  like 
the  prepubic  bones  of  Dimorphodon.  They  have 
sometimes  been  interpreted  as  a  hinder  part  of  the 
sternum,  but  may  more  probably  be  regarded  as  a 
pair  of  prepubic  bones  articulating  each  with  the 
anterior  process  of  the  pubis  (see  Fig.  80).  The  small 
bones  found  at  the  extremities  of  the  pubes  in  such 
carnivorous  Dinosaurs  as  Aristosuchus  are  blended 
by  bony  union  with  the  pubes.  The  bones  in  Igua- 
nodon are  placed  behind  the  sternal  region  without 
any  attachment  for  sternal  ribs,  and  the  expanded 
processes  converge  forwards  from  the  stalk  and  unite 
exactly  like  the  prepubic  bones  of  Ornithosaurs. 
While  this  character,  on  the  one  hand,  may  link 
Pterodactyles  with  the  Dinosaurs,  on  the  other  hand 
it  may  be  a  link  between  both  those  groups  and  the 
Crocodiles,  in  which  the  front  pair  of  bones  of  the 


206  DRAGONS   OF   THE   AIR 

pelvis  has  also  appeared  to  be  representative  of  the 
prepubic  bones  of  Flying  Reptiles  (see  Fig.  32,  p.  98). 
The  resemblances  between  Pterodactyles  and  Dino- 
saurs in  the  hind  limb  are  not  of  less  interest,  though 
it  is  rather  in  the  older  Pterodactyles  such  as  Dimor- 
phodon,  Pterodactylus,  and  Rhamphorhynchus  that 
the  resemblance  is  closest  with  the  slender  car- 
nivorous Dinosaurs.  They  never  have  the  head  of 
the  thigh  bone,  femur,  separated  from  its  shaft  by  a 
constricted  neck,  as  in  the  Pterodactyles  from  the 


Ischii 
Dimorphodon  Iguanodon 

FIG.  8O.       DIAGRAM    OF   THE    PELVIS    SEEN    FROM    BELOW   IN 
AN   ORNITHOSAUR   AND    A    DINOSAUR 


Chalk.  In  many  ways  the  thigh  bone  of  Dinosaurs 
tends  towards  being  Avian  ;  while  that  of  Pterodac- 
tyles inclines  towards  being  Mammalian,  but  with  a 
tendency  to  be  Bird-like  in  the  older  types,  and  to  be 
Mammal-like  in  the  most  recent  representatives  of 
the  group  in  the  Chalk. 

The  bones  of  the  leg  in  Ornithosaurs,  known  as 
tibia  and  fibula,  are  remarkable  for  the  circumstance 
first  that  they  resemble  Birds  in  the  fibula  being  slender 


RELATIONS  OF  PTERODACTYLES     207 

and  only  developed  in  its  upper  part  towards  the 
femur,  and  secondly  that  in  a  genus  like  Dimorpho- 
don  this  drum-stick  bone  has  the  two  upper  bones  of 
the  ankle  blended  with  the  tibia,  so  as  to  form  a 
rounded  pulley  joint  which  is  indistinguishable  from 
that  of  a  Bird  (see  p.  102).  There  is  a  large  number 
of  Dinosaurs  in  which  this  remarkable  distinctive 
character  of  Birds  is  also  found.  Only,  Dinosaurs 
like  Iguanodon,  for  instance,  have  the  slender  fibula 
as  long  as  the  tibia,  and  contributing  to  unite  with  the 
separate  ankle  bones  of  the  similarly  rounded  pulley 
at  the  lower  end.  There  are  no  Birds  in  which  the 
tarsal  bones  remain  separated  and  distinct  through- 
out life.  But  in  Pterodactylus  from  Solenhofen,  as 
in  a  number  of  Dinosaurs,  especially  the  carnivorous 
genera,  the  bones  of  the  tarsus  remain  distinct  through- 
out life,  and  never  acquired  such  forms  as  would  have 
enabled  the  ankle  bone,  termed  astragalus,  to  embrace 
the  extremity  of  the  tibia,  as  it  does  in  Iguanodon. 
Thus  the  resemblance  of  the  Ornithosaur  drum-stick 
is  almost  as  close  to  Dinosaurs  as  to  Birds. 

There  is  great  similarity  between  Dinosaurs  and 
Pterodactyles  seen  in  the  region  of  the  instep,  known 
as  the  metatarsus.  These  bones  are  usually  four  in 
number,  parallel  to  each  other,  and  similar  in  form. 
They  are  commonly  longer  than  in  Dinosaurs ;  but 
among  some  of  the  carnivorous  Dinosaurs  their 
length  approximates  to  that  seen  in  Pterodactyles. 
In  neither  group  are  the  bones  blended  together  by 
bony  union,  while  they  are  always  united  in  Birds,  as 
in  Oxen  and  similar  even-hoofed  mammals.  Dinosaurs 
agree  with  Pterodactyles  in  maintaining  the  metatarsal 
bones  separate,  but  they  differ  from  them  and  agree 
with  Birds  frequently,  in  having  the  number  of  meta- 


208  DRAGONS   OF   THE   AIR 

tarsal  bones  reduced  to  three,  as  in  Iguanodon,  though 
Dinosaurs  often  have  as  many  as  five  digits  developed. 

The  toe  bones,  the  phalanges  of  these  digits  of  the 
hind  limb,  are  usually  longer  in  Pterodactyles  than  in 
Dinosaurs,  but  they  resemble  carnivorous  Dinosaurs 
in  the  forms  of  their  sharp  terminal  bones  for  the  claws, 
which  are  similarly  compressed  from  side  to  side. 

So  diverse  are  the  functions  of  the  fore  limb  in 
Dinosaurs  and  Pterodactyles,  and  so  remarkably  does 
the  length  of  the  metacarpal  region  of  the  back  of  the 
hand  vary  in  the  long-tailed  and  short-tailed  Ornitho- 
saurs,  that  there  is  necessarily  a  less  close  correspond- 
ence in  that  region  of  the  skeleton  between  these  two 
groups  of  animals ;  for  the  Pterodactyle  fore  limb  is 
modified  in  relation  to  a  function  which  can  only  be 
paralleled  among  Birds  and  Bats ;  and  yet  neither 
of  those  groups  of  animals  approximates  closely  in 
this  region  of  the  skeleton  to  the  Flying  Reptile. 
Under  all  the  modifications  of  structure  which  may 
be  attributed  to  differences  of  function,  some  re- 
semblance to  Dinosaurs  may  be  detected,  which  is 
best  evident  in  the  upper  arm  bone,  humerus ;  is 
slight  in  the  fore-arm  bones,  ulna  and  radius;  and 
becomes  lost  towards  the  extremity  of  the  limb. 

If  the  tendency  of  the  thigh  bone  to  resemble  a 
Mammalian  type  of  femur  (p.  100)  is  a  fundamental, 
deep-seated  character  of  the  skeleton,  it  might  be  an- 
ticipated that  a  trace  of  Mammalian  character  would 
also  be  found  in  the  humerus.  For  what  the  character 
is  worth,  the  head  of  the  humerus  does  show  a  closer 
approximation  to  a  Monotreme  Mammal  than  is  seen 
in  Birds,  and  is  to  some  extent  paralleled  in  those 
South  African  reptiles  which  approximate  to  Mammals 
most  closely.  Not  the  least  remarkable  of  the  many 


RELATIONS  OF  PTERODACTYLES     209 

astonishing  resemblances  of  these  light  aerial  creatures 
to  the  more  heavy  bodied  Dinosaurs  is  the  circum- 
stance that  the  humerus  in  both  groups  makes  a  not 
dissimilar  approach  to  that  of  certain  Mammals. 

These  illustrations  may  be  accepted  as  demon- 
strating a  relationship  between  the  Ornithosaurs  and 
Dinosaurs  now  compared,  which  can  only  be  ex- 
plained as  results  of  influence  of  a  common  parentage 
upon  the  forms  of  the  bones.  But  more  interesting 
than  resemblances  of  that  kind  is  the  similarity  that 
may  be  traced  in  the  way  in  which  air  is  introduced 
into  cavities  in  the  bones  in  both  groups.  In  some 
of  the  imperfectly  known  Dinosaurs,  like  Aristosuchus, 
Coelurus,  and  Thecospondylus,  the  bone  texture  is  as 
thin  as  in  Pterodactyles,  and  the  vertebrae  are  ex- 
cavated by  pneumatic  cavities,  which  are  amazing  in 
size  when  compared  with  the  corresponding  structures 
in  birds,  for  the  vertebra  is  often  hollowed  out  so  that 
nothing  remains  but  a  thin  external  film  like  paper 
for  its  thickness.  In  the  Dinosaurian  genus  Ccelurus 
this  condition  is  as  well  marked  in  the  tail  and  back 
as  it  is  in  the  neck.  The  essential  difference  from 
Birds  appears  to  be  that  in  the  larger  carnivorous 
Dinosaurs  the  pneumatic  condition  of  the  bones  is 
confined  to  the  vertebral  column  ;  while  Birds  and 
Pterodactyles  have  the  pneumatic  condition  more 
conspicuously  developed  in  the  limb  bones.  The 
pneumatic  skeleton,  however,  appears  to  be  absent 
from  the  herbivorous  types  like  Iguanodon  and  all 
Dinosaurs  which  have  the  Bird-like  form  of  pelvis, 
and  are  most  Bird-like  in  the  forms  of  bones  of  the 
hind  limb.  It  is  possible  that  some  of  the  carnivorous 
Dinosaurs  also  possessed  limb  bones  with  pneumatic 
cavities.  Many  of  those  bones  are  hollow  with  very 


210  DRAGONS   OF   THE   AIR 

thin  walls.  If  their  cavities  were  connected  with  the 
lungs  the  foramina  are  inconspicuous  and  unlike  the 
immense  holes  seen  in  the  sides  of  the  vertebrae. 

According  to  the  late  Professor  Marsh,  the  limbs 
of  Coelurus  and  its  allies,  which  at  present  are  im- 
perfectly known,  are  in  some  cases  pneumatic.  There- 
fore there  is  a  closer  fundamental  resemblance  be- 
tween some  carnivorous  Dinosaurs  and  Pterodactyles 
than  might  have  been  anticipated.  But  the  skull  of 
Ccelurus  is  unknown,  and  the  fragments  of  the 
skeleton  hitherto  published  are  insufficient  to  do 
more  than  show  that  the  two  types  were  near  in 
kindred,  though  distinct  in  habit.  Each  has  elabo- 
rated a  skeleton  which  owes  much  to  the  common 
stock  which  transmitted  the  vital  organs,  and  the  ten- 
dency of  the  bones  to  take  special  forms ;  but  which 
also  owes  more  than  can  be  accurately  measured  to 
the  action  of  muscles  in  shaping  the  bones  and  the 
influence  of  the  mechanical  conditions  of  daily  life 
upon  the  growth  of  the  bones  in  both  of  these  orders 
of  animals.  Enough  is  known  to  prove  that  all  Dino- 
saurs cannot  be  regarded  as  Ornithosaurs  which  have 
not  acquired  the  power  of  flight ;  though  the  evidence 
would  lead  us  to  believe  that  the  primitive  Ornitho- 
saur  was  a  four-footed  animal,  before  the  wing  finger 
became  developed  in  the  fore  limb  as  a  means  of 
extending  a  patagial  membrane,  like  the  membrane 
which  in  the  hind  limb  of  Dimorphodon  has  bent  the 
outermost  digit  of  the  foot  upward  and  outward  to 
support  the  corresponding  organ  of  flight  extending 
down  the  hind  legs. 

It  may  thus  be  seen  that  the  characters  of  Ornitho- 
saurs which  have  already  been  spoken  of  as  Reptilian, 
as  distinguished  from  the  resemblances  to  Birds,  may 


RELATIONS  OF  PTERODACTYLES     211 

now  with  more  accuracy  be  regarded  as  Dinosaur- 
ian.  The  Dinosaurs,  like  Pterodactyles,  must  be  re- 
garded as  intermediate  in  some  respects  between 
Reptiles  and  Birds.  The  resemblances  enumerated 
would  alone  constitute  a  partial  transition  from  the 
Reptile  to  the  Bird,  although  no  Dinosaurs  have 
organs  of  flight ;  many  are  heavily  armoured  with 
plates  of  bone,  and  few,  if  any,  approximate  in  the 
technical  parts  of  the  skeleton  to  the  Bird  class, 
except  in  the  hind  limbs.  Yet  Dinosaurs  have 
sometimes  been  regarded  as  standing  to  Birds  in 
the  relation  of  ancestors,  or  as  parallel  to  an 
ancestral  stock. 

Before  an  attempt  can  be  made  to  estimate  the 
mutual  relation  of  the  Flying  Reptiles  to  Dinosaurs 
on  the  one  hand,  and  to  Birds  on  the  other,  it  may 
be  well  to  remember  that  the  resemblance  of  such 
a  Dinosaur  as  Iguanodon  to  a  Bird  in  its  pelvis  and 
hind  limb  is  not  more  remarkable  than  that  of 
Pterodactyles  to  Birds  in  the  shoulder-girdle  and 
bones  of  the  fore  limb.  The  keeled  sternum,  the 
long,  slender  coracoid  bones  and  scapulae,  are  abso- 
lutely Bird-like  in  most  Ornithosaurs  ;  and  that  region 
of  the  skeleton  only  differs  from  Birds  in  the  absence 
of  a  furculum  which  represents  the  clavicles,  and  is 
commonly  named  the  "merry-thought."  The  elon- 
gated bones  of  the  fore-arm  and  the  hand,  terminat- 
ing in  three  sharp  claws,  are  characters  in  which  the 
fossil  bird  Archaeopteryx  resembles  the  Pterodactyle 
Rhamphorhynchus,  a  resemblance  which  extends  to 
a  similar  elongation  of  the  tail.  It  is  remarkable 
that  the  resemblance  should  be  so  close,  since  Archae- 
opteryx  affords  the  only  bird's  skeleton  known  to  be 
contemporary  which  can  be  compared  with  the  Solen- 


212  DRAGONS   OF   THE   AIR 

hofen  Flying  Reptiles.  The  resemblance  may  possibly 
be  closer  than  has  been  imagined.  The  back  of  the 
head  of  Archaeopteryx  is  imperfectly  preserved  in 
the  region  of  the  quadrate  bone,  malar  arch,  and 
temporal  vacuity.  And  till  these  are  better  known 
it  cannot  be  affirmed  that  the  back  of  the  head  is 
more  Reptilian  in  Pterodactyles  than  in  the  oldest 
Birds.  The  side  of  the  head  in  Archaeopteryx  is 
distinguished  by  the  nostril  being  far  forward,  the 
vacuity  in  front  of  the  orbit  being  as  large  as  in 
the  Pterodactyle  Scaphognathus  from  Solenhofen 
and  other  long-tailed  Pterodactyles. 


CHAPTER  XVIII 

HOW   PTERODACTYLES    MAY 
HAVE   ORIGINATED 

/^vRNITHOSAURIA  have  many  characters  in- 
V-x  separably  blended  together  which  are  otherwise 
distinctive  of  Reptiles,  Birds,  and  Mammals,  and  as- 
sociated with  peculiar  structures  which  are  absent 
from  all  other  animals.  They  are  not  quite  alone  in 
this  incongruous  combination  of  different  types  of 
animals  in  the  same  skeleton.  Dinosaurs,  which  were 
contemporary  with  Ornithosaurs,  approximate  to  them 
in  blending  characters  of  Birds  with  the  structure  of 
a  Reptile  and  something  of  a  Mammal  in  one  animal. 
If  an  Ornithosaur  is  Reptilian  in  its  backbone,  in  the 
articular  ends  of  each  vertebra  having  the  cup  in 
front  and  ball  behind  in  the  manner  of  Crocodiles, 
Serpents,  and  many  Lizards,  a  Dinosaur  like  Iguano- 
don,  which  had  the  reversed  condition  of  ball  in 
front  and  cup  behind  in  its  early  vertebrae,  may  be 
more  Mammalian  than  Avian  in  a  corresponding 
resemblance  of  the  bones  to  the  neck  in  hoofed 
Mammals.  But  while  Pterodactyles  are  sometimes 
Mammalian  in  having  the  head  of  the  thigh  bone 
moulded  as  in  carnivorous  Mammals  and  Man,  the 
corresponding  bone  in  a  Dinosaur  is  more  like  that 
213 


214  DRAGONS    OF   THE   AIR 

of  a  Bird.  And  while  the  Pterodactyle  shoulder- 
girdle  is  often  absolutely  Bird-like,  that  region  in 
Dinosaurs  can  only  be  paralleled  among  Reptiles. 

Such  combinations  of  diverse  characters  are  not 
limited  to  animals  which  are  extinct.  There  were 
not  wanting  scientific  men  who  regarded  the  Platy- 
pus of  Australia,  when  first  sent  to  Europe,  as  an 
ingenious  example  of  Eastern  skill,  in  which  an 
animal  had  been  compounded  artificially  by  blend- 
ing the  beak  of  a  Bird  with  the  body  of  a  Mammal. 
Fuller  knowledge  of  that  remarkable  animal  has 
continuously  intensified  wonder  at  its  combination 
of  Mammal,  Bird,  and  Reptile  in  a  single  animal. 
It  has  broken  down  the  theoretical  divisions  be- 
tween the  higher  Vertebrata,  demonstrating  that  a 
Mammal  may  lay  eggs  like  a  Reptile  or  Bird,  that 
the  skull  may  include  the  reptilian  characters  of  the 
malar  arch  and  pre-frontal  and  post-frontal  bones, 
otherwise  unknown  in  Mammals  and  Birds.  The 
groups  of  Mammals,  Birds,  and  Reptiles  now  sur- 
viving on  the  earth  prove  to  be  less  sharply  defined 
from  each  other  when  the  living  and  extinct  types 
are  considered  together.  But  in  Pterodactyles, 
Mammal  Bird  and  Reptile  lose  their  identity,  as  three 
colours  would  do  when  unequally  mixed  together. 

This  mingling  of  characteristics  of  different  animals 
is  not  to  be  attributed  to  interbreeding,  but  is  the 
converse  of  the  combination  of  characters  found  in 
hybrid  animals.  It  is  no  exaggeration  to  say  that 
there  is  a  sense  in  which  Mammal,  Bird,  Reptile,  and 
the  distinctive  structures  of  the  Ornithosaur,  have 
simultaneously  developed  from  one  egg,  in  the  body 
of  one  animal. 

The  differences  between  those  vertebrate  types  of 


ORIGIN   OF   PTERODACTYLES       215 

animals  consist  chiefly  in  the  way  in  which  their 
organisation  is  modified,  by  one  strain  of  characters 
being  eliminated  so  that  another  becomes  predomi- 
nant, while  a  distinctive  set  of  structures  is  elaborated 
in  each  class  of  animals.  The  earlier  geological  his- 
tory of  the  higher  Vertebrata  is  very  imperfectly 
known,  but  the  evidence  tends  to  the  inference  that 
the  older  representatives  of  the  several  classes  ap- 
proximate to  each  other  more  closely  than  do  their 
surviving  representatives,  so  that  in  still  earlier  ages 
of  time  the  distinction  between  them  had  not  become 
recognisable.  The  relation  of  the  great  groups  of 
animals  to  each  other,  among  Vertebrata,  is  essentially 
a  parallel  relation,  like  the  colours  of  the  solar  spec- 
trum, or  the  parallel  digits  of  the  hand.  It  was 
natural,  when  only  the  surviving  life  on  the  earth  was 
known,  to  imagine  that  animals  were  connected  in  a 
continuous  chain  by  successive  descent,  but  Mammals 
have  given  no  evidence  of  approximation  to  Birds; 
and  Birds  discover  no  evidence  that  their  ancestors 
were  Reptiles,  in  the  sense  in  which  that  word  is  used 
to  define  animals  which  now  exist  on  the  earth. 
When  the  variation  which  animals  attain  in  their 
maturity  and  exhibit  in  development  from  the  egg 
was  first  realised,  it  was  imagined  that  Nature,  by 
slow  summing  up  and  accumulation  of  differences 
which  were  observed,  would  so  modify  one  animal 
type  that  it  would  pass  into  another.  There  is  little 
evidence  to  support  belief  that  the  changes  between 
the  types  of  life  have  been  wrought  in  that  way. 
The  history  of  fossil  animals  has  not  shown  transi- 
tions of  this  kind  from  the  lower  to  higher  Vertebrata, 
but  only  intermediate,  parallel  groups  of  animals, 
analogous  to  those  which  survive,  and  distinct  from 


216  DRAGONS   OF   THE   AIR 

them  in  the  same  way  as  surviving  groups  are  distinct 
from  each  other.  The  circumstance  that  Mammals, 
Birds,  and  Reptiles  are  all  known  low  down  in  the 
Secondary  epoch  of  geological  time,  is  favourable  to 
the  idea  of  their  history  being  parallel  rather  than 
successive.  Such  a  conception  is  supported  by  the 
theory  of  elimination  of  characters  from  groups  of 
animals  as  the  basis  of  their  differentiation.  This  loss 
appears  always  to  be  accompanied  by  a  correspond- 
ing gain  of  characters,  which  is  more  remarkable  in 
the  soft,  vital  organs  than  in  the  skeleton.  The  gain 
in  higher  Vertebrates  in  the  bones  is  chiefly  in  the 
perfection  of  joints  at  their  extremities  ;  but  the  gain 
in  brain,  lungs,  heart,  and  other  soft  parts  is  an 
elaboration  of  those  structures  and  an  increase  in 
amount  of  tissue. 

The  resemblances  of  Ornithosaurs  to  Mammals  are 
the  least  conspicuous  of  their  characters.  Those  seen 
in  the  upper  arm  bone  and  thigh  bone  are  manifestly 
not  derived  from  Mammals.  They  cannot  be  ex- 
plained as  adaptations  of  the  bones  to  conditions  of 
existence,  because  there  is  no  community  of  habit  to 
be  inferred  between  Pterodactyles  and  Mammals,  in 
which  the  bones  are  in  any  way  comparable. 

Other  fossil  animals  show  that  a  fundamentally 
Reptilian  structure  is  capable  of  developing  in  the 
Mammalian  direction  in  the  skull,  backbone,  shoulder- 
girdle,  hip-girdle,  and  limbs,  so  as  to  be  uniformly 
Mammalian  in  its  tendencies.  This  is  proved  by 
tracing  the  North  American  Texas  fossils  named 
Labyrinthodonts,  through  the  South  African  Therio- 
donts,  towards  the  Monotremata  and  other  Mammalia. 
Just  as  those  animals  have  obliterated  all  traces  of 
the  Bird  from  their  skeletons,  Birds  have  obliterated 


ORIGIN   OF   PTERODACTYLES       217 

the  distinctive  characters  of  Mammals.  The  Ornitho- 
saur  has  partially  obliterated  both.  With  a  skull  and 
backbone  marked  by  typical  characters  of  the  Reptile, 
it  combines  the  shoulder-girdle  and  hip-girdle  of  a 
Bird,  with  characters  in  the  limbs  which  suggest  both 
those  types  in  combination  with  Mammals. 

The  bones  have  been  compared  in  the  skeleton  of 
each  order  of  existing  Reptiles,  and  found  to  show 
side  by  side  with  their  peculiar  characters  not  only 
resemblances  to  the  other  Reptilia,  but  an  appreciable 
number  of  Mammalian  and  Avian  characters  in  their 
skeletons.  The  term  "  crocodile,"  for  example,  indi- 
cates an  animal  in  which  the  skeleton  is  dominated 
by  one  set  of  peculiar  characters.  Crocodiles  retain 
enough  of  the  characteristics  of  several  other  orders 
of  reptiles  to  show  that  an  animal  sprung  from  the 
old  Crocodile  stock  might  diverge  widely  from  exist- 
ing Crocodiles  by  intensifying  what  might  be  termed 
its  dormant  characters  in  the  Crocodile  skeleton. 
Comparing  animals  together  bone  by  bone  it  is 
possible  to  value  the  modifications  of  form  which 
they  put  on,  and  the  resemblances  between  them, 
so  as  to  separate  the  inherited  wealth  of  an  animal's 
affinities  with  ancestors  or  collateral  groups,  from 
the  peculiar  characters  which  have  been  acquired 
as  an  increase  based  upon  its  typical  bony  possessions 
or  osteological  capital.  There  is  no  part  of  the  Ptero- 
dactyle  skeleton  which  is  more  distinctly  modified 
than  the  head  of  the  upper  arm  bone,  which  fits 
into  the  socket  between  the  coracoid  bone  and  the 
shoulder-blade.  The  head  of  the  humerus,  as  the 
articular  part  is  named,  is  somewhat  crescent-shaped, 
convex  on  its  inner  border,  and  a  little  concave  on 
its  outer  border,  and  therefore  unlike  the  ball-shaped 


218  DRAGONS   OF   THE   AIR 

head  of  the  upper  arm  bone  in  Man  and  the  higher 
Mammals.  It  is  much  more  nearly  paralleled  in  the 
little  group  of  Monotremata  allied  to  the  living 
Ornithorhynchus.  In  that  sense  the  head  of  the 
humerus  in  a  Pterodactyle  has  some  affinity  with  the 
lowest  Mammalia,  which  approach  nearest  to  Reptiles. 
The  character  might  pass  unregarded  if  it  were  not 
found  in  more  striking  development  in  fossil  Reptiles 
from  Cape  Colony,  which  from  having  teeth  like 
Mammals  are  named  Theriodontia.  In  several  of 
those  South  African  reptiles  the  upper  arm  bone 
approaches  closer  to  the  humerus  in  Ornithosaurs 
than  to  Ornithorhynchus.  Such  coincidences  of 
structure  are  sometimes  dismissed  from  considera- 
tion and  placed  beyond  investigation  by  being  termed 
adaptive  modifications ;  but  there  can  be  no  hope 
of  finding  community  of  habit  between  the  burrow- 
ing Monotreme,  the  short-limbed  Theriodont,  and 
the  flying  Pterodactyle  which  might  have  caused 
this  articular  part  of  the  upper  arm  bone  to  acquire 
a  form  so  similar  in  animals  constructed  so  differ- 
ently. If  the  resemblance  in  the  humerus  to  Mono- 
tremes  in  this  respect  is  not  to  be  attributed  to 
burrowing,  neither  can  the  crescent  form  of  its  upper 
articulation  be  attributed  to  flight ;  for  in  Birds  the 
head  of  the  bone  is  compressed,  but  always  convex, 
and  Bats  fly  without  any  approach  to  the  Ptero- 
dactyle form  in  the  head  of  the  humerus.  This 
apparently  trivial  character  may  from  such  com- 
parisons be  inferred  to  be  something  which  the  way 
of  life  of  the  animal  does  not  sufficiently  account  for. 
These  deepest-seated  parts  of  the  limbs  are  slow  to 
adapt  themselves  to  changing  circumstances  of  exist- 
ence, and  retain  their  characters  with  moderate 


ORIGIN   OF   PTERODACTYLES       219 

variation  of  the  bones  in  each  of  the  orders  or  classes 
of  animals.  It  therefore  is  safer  to  regard  Mamma- 
lian characters,  as  well  as  the  resemblances  which 
Pterodactyles  show  to  other  kinds  of  animals,  as  due 
to  inheritance  from  a  time  when  there  was  a  common 
stock  from  which  none  of  these  animals  which  have 
been  considered  had  been  distinctly  elaborated. 

A  few  characters  of  Ornithosaurs  are  regarded  as 
having  been  acquired,  because  they  are  not  found 
in  any  other  animals,  or  have  been  developed  only 
in  a  portion  of  the  group.  The  most  obvious  of 
these  is  the  elongated  wing  finger;  but  in  some 
genera,  like  Dimorphodon,  there  is  also  a  less  elonga- 
tion of  the  fifth  digit  of  the  foot,  and  perhaps  in 
all  genera  there  is  a  backward  development  of  the 
first  digit  of  the  hand,  which  is  without  a  claw,  and 
therefore  unlike  the  clawed  digit  of  a  Bat.  An 
acquired  character  of  another  kind,  which  is  limited 
to  the  Cretaceous  genera,  is  seen  in  the  shoulder- 
blade  being  directed  transversely  outward,  so  that 
its  truncated  end  articulates  by  a  true  joint  with  the 
early  vertebras  of  the  back,  and  defended  the  cavity 
inclosed  by  the  ribs  by  a  strong  bony  external  arch. 
And  finally,  as  the  animals  later  in  time  acquire  short 
tails,  and  relatively  longer  limbs,  the  bones  of  the 
back  of  the  hand,  termed  metacarpals,  acquire 
greater  and  distinctive  length,  which  is  not  seen  in 
the  long-tailed  types  like  Rhamphorhynchus. 

These  and  such-like  acquired  characters  distin- 
guish the  class  of  animals  from  all  groups  with 
which  it  may  be  compared,  and  mark  the  possible 
limits  of  variation  of  the  skeleton  within  the 
boundary  of  the  order.  But  no  further  variation  of 
these  parts  of  the  skeleton  could  make  a  transition 


220  DRAGONS   OF   THE   AIR 

to  another  order  of  animals,  or  explain  how  the 
Pterodactyles  came  into  existence,  because  the  char- 
acters which  separate  orders  and  classes  of  animals 
from  each  other  differ  in  kind  from  those  which 
separate  smaller  groups,  named  genera  and  species, 
of  which  the  order  is  made  up.  The  accumulation 
of  the  characters  of  genera  will  not  sum  up  into  the 
characters  of  an  order  or  class. 

In  making  the  division  of  Vertebrate  animals  into 
classes  the  skeleton  is  often  almost  ignored.  Its 
value  is  entirely  empirical  and  based  upon  the 
observed  association  of  the  various  forms  of  bones 
with  the  more  important  characters  of  the  brain  and 
other  vital  organs.  What  is  understood  as  a  Mamma- 
lian or  Avian  character  in  the  skeleton  is  the  form 
of  bone  which  is  found  in  association  with  the  soft 
vital  organs  which  constitute  an  animal  a  Mammal 
or  a  Bird. 

The  characters  which  theoretically  define  a  Mammal 
appear  to  be  the  enormous  overgrowth  of  the  cerebral 
hemispheres  of  the  brain  by  which  the  cerebrum 
comes  into  contact  with  the  cerebellum,  as  among 
Birds.  This  character  distinguishes  both  groups  of 
animals  from  all  Reptiles,  recent  and  fossil.  But  in 
examining  the  mould  of  the  interior  of  the  brain 
case  it  is  rare  to  have  the  bones  fitting  so  closely 
to  the  brain  as  to  prove  that  the  lateral  expansion 
below  the  cerebrum  and  cerebellum  is  formed  by 
the  optic  lobes  of  the  brain.  Otherwise  the  brain 
of  a  Pterodactyle  might  be  as  like  to  the  brain  of 
Ornithorhynchus  as  it  is  like  that  of  a  Bird  (Fig.  19). 
But  it  is  precisely  in  this  condition  of  arrangement 
of  the  parts  of  the  brain  that  the  specimens  appear 
to  be  most  clear.  The  lateral  mass  of  brain  in 


ORIGIN   OF   PTERODACTYLES       221 

specimens  of  Ornithosaurs  from  the  Lower  Secondary 
rocks  appears  to  be  transversely  divided  into  back 
and  front  parts,  which  may  be  thought  to  corre- 
spond to  the  structures  in  a  Mammal  brain  named 
corpora  quadrigemina,  but  to  be  placed  as  the  optic 
lobes  are  placed  in  Birds,  and  to  have  relatively 
greater  dimensions  than  in  Mammals.  No  evidence 
has  been  observed  of  this  transverse  division  of  the 
optic  lobes  of  the  brain  in  Pterodactyles  from  the 
Chalk  and  Cretaceous  rocks,  and  so  far  as  the  evidence 
goes  this  part  of  the  brain  was  shaped  as  in  birds, 
but  rather  smaller. 

The  brain  is  the  only  soft  organ  in  which  a  Mam- 
malian character  could  be  evidenced.  The  uniformity 
in  character  of  the  brain  throughout  the  group  in 
Mammals  is  remarkable,  in  reference  to  the  circum- 
stance that  the  reproduction  varies  in  type ;  the  lowest, 
or  Monotreme  division,  being  oviparous.  If  there  is 
no  necessary  connexion  between  the  Mammalian 
brain  and  the  prevalent  condition  under  which  the 
young  are  produced  alive,  it  may  be  affirmed  also 
that  there  is  no  necessary  connexion  between  the 
form  of  the  brain  and  the  form  of  the  bones,  since 
the  brain  cavity  in  Theriodont  reptiles  shows  no 
resemblance  to  that  of  a  Mammal,  while  the  bones 
are  in  so  many  respects  only  paralleled  among 
Monotremata  and  Mammalia.  The  variety  of  forms 
which  the  existing  Mammalian  orders  of  animals 
assume,  shows  the  astonishing  range  of  structure  of 
the  skeleton  which  may  coexist  with  the  Mammalian 
brain.  And  therefore  we  are  led  to  the  conclusion 
that  any  other  fundamental  modification  of  brain — 
such  as  distinguishes  the  class  of  Birds— might  also 
be  associated  with  forms  and  structures  of  the  skele- 


222  DRAGONS   OF   THE   AIR 

ton  which  would  vary  in  similar  ways.  In  other 
words,  if  for  convenience  we  define  a  Mammal  by 
its  form  of  brain,  structure  of  the  heart  and  lungs, 
and  provision  for  nutrition  of  the  young,  without 
regard  to  the  covering  of  the  skin,  which  varies 
between  the  scales  of  a  pangolin  and  the  practically 
naked  skin  of  the  whale — a  bird  might  be  also 
defined  by  its  peculiar  conditions  of  brain  and  lungs, 
without  reference  to  the  feathered  condition  of  the 
skin,  though  the  feathered  condition  extends  back- 
ward in  time  to  the  Upper  Secondary  rocks,  as  seen 
in  the  Archaeopteryx. 

The  Avian  characters  of  Pterodactyles  are  the  pre- 
dominant parts  of  their  organisation,  for  the  con- 
ditions of  the  brain  and  lungs  shown  by  the  moulds 
of  the  brain  case  and  the  thin  hollow  bones  with 
conspicuous  pneumatic  foramina,  give  evidence  of 
a  community  of  vital  structures  with  Birds,  which 
is  supported  by  characters  of  the  skeleton.  If  any 
classificational  value  can  be  associated  with  the  distri- 
bution of  the  pneumatic  foramina  as  tending  to 
establish  membership  of  the  same  class  for  animals 
fashioned  on  the  same  plan  of  soft  organs,  the 
evidence  is  not  weakened  when  a  community  of 
structures  is  found  to  extend  among  the  bones  to 
such  distinctive  parts  of  the  skeleton  as  the  sternum, 
shoulder-girdle,  bones  of  the  fore-arm  and  fore-leg; 
for  in  all  these  regions  the  Pterodactyle  bones  are 
practically  indistinguishable  from  those  of  Birds. 
This  is  the  more  remarkable  because  other  parts  of 
the  skeleton,  such  as  the  humerus  and  pelvis,  show 
a  partial  resemblance  to  Birds,  while  the  parts  which 
are  least  Avian,  like  the  neck  bones,  have  no  ten- 
dency to  vary  the  number  of  the  vertebrae,  in  the 


ORIGIN   OF   PTERODACTYLES       223 

way  which  is  common  among  Birds,  following  more 
closely  the  formula  of  the  seven  cervical  vertebrae  of 
Mammals. 

It  would  therefore  appear  from  the  vital  com- 
munity of  structures  with  Birds,  that  Pterodactyles 
and  Birds  are  two  parallel  groups,  which  may  be 
regarded  as  ancient  divergent  forks  of  the  same 
branch  of  animal  life,  which  became  distinguished 
from  each  other  by  acquiring  the  different  condition 
of  the  skin,  and  the  structures  which  were  developed 
in  consequence  of  the  bony  skeleton  ministering  to 
flight  in  different  ways  ;  and  with  different  habit  of 
terrestrial  progression,  this  extinct  group  of  animals 
acquired  some  modifications  of  the  skeleton  which 
Birds  have  not  shown.  There  is  nothing  to  suggest 
that  Pterodactyles  are  a  branch  from  Birds,  but  their 
relation  to  Birds  is  much  closer,  so  far  as  the  skeleton 
goes,  than  is  their  relation  with  the  flightless  Dino- 
saurs, with  which  Birds  and  Pterodactyles  have  many 
characters  in  common. 

On  the  theory  of  elimination  of  character  which 
I  have  used  to  account  for  the  disappearance  of  some 
Mammalian  characters  from  the  Pterodactyle,  that 
loss  is  seen  chiefly  in  the  removal  of  the  parts  which 
have  left  a  Reptilian  articulation  of  the  lower  jaw 
with  the  skull,  and  the  articulation  of  the  vertebrae 
throughout  the  vertebral  column  by  a  modified  cup- 
and-ball  form  of  joint  The  furculum  of  the  Bird  is 
always  absent  from  the  Pterodactyle.  No  specimen 
has  shown  recognisable  clavicles  or  collar-bones. 
Judged  by  the  standard  of  existing  life,  Pterodac- 
tyles belong  to  the  same  group  as  Birds,  on  the 
evidence  of  brain  and  lungs,  but  they  belong  to 
a  different  group  on  account  of  the  dissimilar 


224  DRAGONS   OF   THE   AIR 

modifications  of  the  skeleton  and  apparent  absence 
of  feathers  from  the  skin. 

The  most  impressive  facts  in  the  Pterodactyle 
skeleton,  in  view  of  these  affinities,  are  the  structures 
which  it  has  in  common  with  Reptiles.  Some  struc- 
tures are  fundamental,  like  the  cup-and-ball  articula- 
tion of  the  vertebrae,  which  is  never  found  in  birds 
or  mammals.  Although  not  quite  identical  with  the 
condition  in  any  Reptile,  this  structure  is  approxi- 
mately Lizard-like  or  Crocodile-like  in  the  cup-and- 
ball  character.  It  shows  that  the  deepest-seated  part 
of  the  skeleton  is  Reptile-like,  though  it  may  not  be 
more  Reptilian  than  is  the  vertebral  column  of  a 
Mammal,  if  comparison  is  made  between  Mammals 
and  extinct  groups  of  animals  known  as  Reptiles, 
such  as  Dinosaurs  and  Theriodontia. 

The  orders  of  animals  which  have  been  included 
under  the  name  Reptilia  comprise  such  different 
structural  conditions  of  the  parts  of  the  skeleton 
which  may  be  termed  reptilian  in  Ornithosaurs,  that 
there  is  good  reason  for  regarding  the  cup-and-ball 
articulation  as  quite  a  distinctive  Reptilian  specialisa- 
tion, in  the  same  sense  that  the  saddle-shaped  articu- 
lation between  the  bodies  of  adjacent  vertebrae  in 
a  bird  is  an  Avian  specialisation.  From  the  theoretical 
point  of  view  the  Ornithosaur  acquired  its  Reptilian 
characters  simultaneously  with  its  Avian  and  Mam- 
malian characters. 

There  is  nothing  in  the  structure  of  the  skeleton 
of  the  Dinosauria,  to  which  Ornithosaurs  approximate 
in  several  parts  of  the  body,  which  would  help  to 
explain  the  cup-and-ball  articulation  of  the  backbone, 
if  the  Flying  Reptile  were  supposed  to  be  an  offshoot 
from  the  carnivorous  Dinosaurs. 


ORIGIN   OF   PTERODACTYLES       225 

The  elimination  of  Reptile  characters  from  so  much 
of  the  skeleton,  and  the  substitution  for  them  of  the 
characters  of  Birds  and  Mammals,  would  be  of  ex- 
ceptional interest  if  there  had  been  any  ground  for 
regarding  the  flying  animal  as  more  nearly  related  to 
a  Reptile  than  to  a  Bird.  But  if  the  evidence  from 
the  form  of  the  brain  and  nature  of  the  pneumatic 
organs  seen  in  the  limb  bones  accounts  for  the  Avian 
features  of  the  skeleton,  the  Reptilian  condition  of  the 
vertebral  column  helps  to  show  a  capacity  for  varia- 
tion, and  that  the  fixity  of  type  and  structure,  which 
the  skeleton  of  the  modern  Bird  has  attained,  is  not 
necessarily  limited  to  or  associated  with  the  vital 
organs  of  Birds. 

The  variation  of  the  cup-and-ball  articulation  in 
the  neck  of  a  Chelonian,  which  makes  the  third 
vertebra  cupped  behind,  the  fourth  bi-convex,  the 
fifth  cupped  in  front,  and  the  sixth  flattened  behind, 
shows  that  too  much  importance  may  be  attached 
to  the  mode  of  union  of  these  bones  in  Serpents, 
Crocodiles,  and  those  Lizards  which  have  the  cup  in 
front ;  for  while  in  Lizards  the  anterior  cup,  oblique  and 
depressed,  is  found  in  most  of  its  groups,  the  Geckos 
show  no  trace  of  the  cup-and-ball  structure,  and  in 
that  respect  resemble  the  Hatteria  of  New  Zealand. 

If,  therefore,  the  cup-and-ball  articulation  of  verte- 
brae in  Ornithosauria  has  any  significance  as  a  mark 
of  affinity  to  Reptiles,  it  could  only  be  in  approxima- 
tion to  those  living  Reptiles  which  possess  the  same 
character,  and  would  have  it  on  the  hypothesis  that 
both  have  preserved  the  structure  by  descent  from  an 
earlier  type  of  animal.  This  hypothesis  is  negatived 
by  the  fact  that  the  cup-and-ball  articulation  is  un- 
known in  the  older  fossil  Reptiles. 
Q 


226  DRAGONS   OF  THE   AIR 

Although  the  articulation  for  the  lower  jaw  with 
the  skull  in  Ornithosaurs  is  only  to  be  paralleled 
among  Reptiles,  the  structure  is  adapted  to  a  brain 
case  which  is  practically  indistinguishable  from  that 
of  a  Bird,  except  for  the  postorbital  arch. 

The  hypothesis  of  descent,  therefore,  becomes  im- 
possible, in  any  intelligible  form,  in  explanation 
of  distinctive  character  of  the  skeleton.  The  hypo- 
thesis of  elimination  may  also  seem  to  be  insufficient, 
unless  the  potential  capacity  for  new  development  be 
recognised  as  concurrent,  and  as  capable  of  modify- 
ing each  region  of  the  skeleton,  or  hard  parts  of  the 
animal,  in  the  same  way  that  the  soft  organs  may  be 
modified.  From  which  we  infer  that  all  structures, 
which  distinguish  the  several  grades  of  organisation 
in  modern  classifications,  soft  parts  and  hard  parts 
alike,  may  come  into  existence  together,  in  so  far 
as  they  are  compatible  with  each  other,  in  any  class 
or  ordinal  division  of  animals. 

Although  the  young  Mammal  passes  through  a 
stage  of  growth  in  which  the  brain  may  be  said  to  be 
Reptilian,  there  is  no  good  ground  for  inferring  that 
Mammal  or  Bird  type  of  skeleton  was  developed  later 
in  time  than  that  of  Reptiles.  The  various  types  of 
Fishes  have  the  brains  in  general  so  similar  to  those 
of  Reptiles  that  it  is  more  intelligible  for  all  the 
vertebrate  forms  of  brain  to  have  differentiated  at 
the  same  time,  under  the  law  of  elimination  of  char- 
acters, than  that  there  should  be  any  other  bond  of 
union  between  the  classes  of  animals. 

If  we  ask  what  started  the  Ornithosauria  into 
existence,  and  created  the  plan  of  construction  of 
that  animal  type,  I  think  science  is  justified  in  boldly 
affirming  that  the  initial  cause  can  only  be  sought 


ORIGIN   OF   PTERODACTYLES       227 

under  the  development  of  patagial  membranes,  such 
as  have  been  seen  in  various  animals  ministering  to 
flight.  Such  membranes,  in  an  animal  which  was 
potentially  a  Bird  in  its  vital  organs,  have  owed  de- 
velopment to  the  absence  of  quill  feathers.  Thus 
the  wing  membrane  may  be  the  cause  for  the  chief 
differences  of  the  skeleton  by  which  Ornithosaurs 
are  separated  from  Birds,  for  the  stretch  of  wing  in 
one  case  is  made  by  the  skin  attached  to  the  bones, 
and  in  the  other  case  by  feathers  on  the  skin  so 
attached  as  to  necessitate  that  the  wing  bones  have 
different  proportions  from  Ornithosaurs. 

It  is  a  well-known  observation  that  each  great 
epoch  of  geological  time  has  had  its  dominant  forms 
of  animal  life,  which,  so  far  as  the  earth's  history  is 
known  now,  came  into  existence,  lived  their  time, 
and  were  seen  no  more.  In  the  same  way  the 
smaller  groups  of  species  and  genera  included  in  an 
ordinal  group  of  animals  or  class  have  abounded, 
giving  a  tone  to  the  life  of  each  geological  formation, 
until  the  vitality  of  the  animal  is  exhausted,  and  the 
species  becomes  extinct  or  ceases  to  preponderate. 
This  process  is  seen  to  be  still  modifying  the  life  on 
the  earth,  when  some  kinds  of  animals  and  plants 
are  introduced  to  new  conditions.  Plants  appear  to 
wage  successful  war  more  easily  than  animals.  The  in- 
troduction of  the  Cactus  in  some  parts  of  Cape  Colony 
has  locally  modified  both  the  fauna  and  flora,  just 
as  the  Anacharis  introduced  into  England  spread 
from  Cambridge  over  the  whole  country,  and  became 
for  many  years  the  predominant  form  of  plant  life 
in  the  streams.  The  Rabbit  in  Australia  is  a  historic 
pest.  Something  similar  to  this  physical  fertility 
and  increase  appears  to  take  place  under  new  cir- 


228  DRAGONS   OF  THE   AIR 

cumstances  in  certain  organs  within  the  bodies  of 
animals,  by  the  development  of  structures  previously 
unknown.  A  familiar  example  is  seen  in  the  internal 
anatomy  of  the  Trout  introduced  into  New  Zealand, 
where  the  number  of  pyloric  appendages  about  the 
stomach  has  become  rapidly  augmented,  while  the 
size  and  the  form  of  the  animal  have  changed.  The 
rapidity  with  which  some  of  these  changes  have  been 
brought  about  would  appear  to  show  that  Nature  is 
capable  of  transforming  animals  more  rapidly  than 
might  have  been  inferred  from  their  uniform  life 
under  ordinary  circumstances.  Growth  of  the  vital 
organs  in  this  way  may  modify  the  distinctive  form 
of  any  vital  organ,  brain  or  lungs,  and  thus  as  a  con- 
sequence of  modification  of  the  internal  structures  due 
to  changes  of  food  and  habit,  bring  a  new  group  of 
animals  into  existence.  And  just  as  the  group  of 
animals  ceases  to  predominate  after  a  time,  so  there 
comes  a  limit  to  the  continued  internal  development 
of  vital  structures  as  their  energy  fails,  for  each  organ 
behaves  to  some  extent  like  an  independent  organism. 
Under  such  explanations  of  the  mutual  relations  of 
the  parts  of  animals,  and  groups  of  animals,  time 
ceases  to  be  a  factor  of  primary  importance  in  their 
construction  or  elaboration.  The  supposed  necessity 
for  practically  unlimited  time  to  produce  changes  in 
the  vital  organs  which  separate  animals  into  great 
orders  or  classes  is  a  nightmare,  born  of  hypothesis, 
and  may  be  profitably  dismissed.  The  geological 
evidence  is  too  imperfect  for  dogmatism  on  specu- 
lative questions ;  but  the  nature  of  the  affinities  of 
Ornithosaurs  to  other  animals  has  been  established 
on  a  basis  of  comparison  which  has  no  need  of 
theory  to  justify  the  facts.  It  is  not  improbable  that 


ORIGIN   OF   PTERODACTYLES       229 

the  primary  epoch  of  time,  even  as  known  at  present, 
may  be  sufficiently  long  to  contain  the  parent  races 
from  which  Ornithosaurs  and  all  their  allies  have 
arisen. 

In  thus  stating  the  relation  of  Ornithosaurs  to 
other  animals  the  Flying  Reptile  has  been  traced 
home  to  kindred,  though  not  to  its  actual  parents  or 
birthplace.  There  is  no  geological  history  of  the 
rapid  or  gradual  development  of  the  wing  ringer,  and 
although  the  wing  membrane  may  be  accepted  as 
its  cause  of  existence,  the  wing  finger  is  powerfully 
developed  in  the  oldest  known  Pterodactyles  as  in 
their  latest  representatives. 

Pterodactyles  show  singularly  little  variation  in 
structure  in  their  geological  history.  We  chronicle 
the  loss  of  the  tail  and  loss  of  teeth.  There  is  also 
the  loss  of  the  outermost  wing  digit  from  the  hind 
foot  as  a  supporter  of  the  wing  membrane.  But  the 
other  variations  are  in  the  length  of  the  metacarpus, 
or  of  the  neck,  or  head.  One  of  the  fundamental 
laws  of  life  necessitates  that  when  an  animal  type 
ceases  to  adapt  its  organisation  and  modify  its 
structures  to  suit  the  altered  circumstances  forced 
upon  it  by  revolutions  of  the  earth's  surface  its  life's 
history  becomes  broken.  It  must  bend  or  break. 

The  final  disappearance  of  these  animals  from  the 
earth's  history  in  the  Chalk  may  yet  be  modified 
by  future  discoveries,  but  the  Flying  Reptiles  have 
vanished,  in  the  same  way  as  so  many  other  groups 
of  animals  which  were  contemporary  with  them  in 
the  Secondary  period  of  time.  Such  extinctions 
have  been  attributed  to  catastrophes,  Jike  the  sub- 
mergence of  land,  so  that  the  habitations  of  animals 
became  an  area  gradually  decreasing  in  size,  which 


230  DRAGONS   OF  THE  AIR 

at  last  disappeared.  It  appears  also  to  be  a  law  of 
life,  illustrated  by  many,  extinct  groups  of  animals, 
that  they  endure  for  geological  ages,  and  having 
fought  their  battle  in  life's  history,  grow  old  and  un- 
able to  continue  the  fight,  and  then  disappear  from 
the  earth,  giving  place  to  more  vigorous  types  adapted 
to  live  under  new  conditions. 

The  extinct  Pterodactyles  hold  a  relation  to  Birds 
in  the  scheme  of  life  not  unlike  that  which  Mono- 
tremata  hold  to  other  Mammals.  Both  are  remark- 
able for  the  variety  of  their  affinities  and  resemblances 
to  Reptiles.  The  Ornithosauria  have  long  passed 
away  ;  the  Monotremes  are  nearing  extinction.  Both 
appear  to  be  supplanted  by  parallel  groups  which 
were  their  contemporaries.  Birds  now  fill  the  earth 
in  a  way  that  Flying  Reptiles  never  surpassed;  but 
their  flight  is  made  in  a  different  manner,  and  the 
wing  is  extended  to  support  the  animal  in  the  air, 
chiefly  by  appendages  to  the  skin. 

If  these  fossils  have  taught  that  Ornithosaurs  have 
a  community  of  soft  vital  organs  with  Dinosaurs  and 
Birds,  they  have  also  gone  some  way  towards  proving 
that  causes  similar  to  those  which  determined  the 
structural  peculiarities  of  their  bony  framework, 
originated  the  special  forms  of  respiratory  organs 
and  brain  which  lifted  them  out  of  association  with 
existing  Reptiles. 

These  old  flying  animals  sleep  through  geological 
ages,  not  without  honour,  for  the  study  of  their  story 
has  illuminated  the  mode  of  origin  of  animals  which 
survive  them,  and  in  cleaving  the  rocks  to  display 
their  bones  we  have  opened  a  new  page  of  the  book 
of  life. 


APPENDIX 

THE  best  public  collections  of  Ornithosaurian  remains  in 
England  are  in  the  British  Museum  (Natural  History) ; 
Museum  of  Practical  Geology,  Royal  College  of  Surgeons ; 
the  University  Museum,  Oxford ;  Geological  Museum, 
Cambridge ;  and  the  Museum  of  the  Philosophical  Society 
at  York. 

Detailed  descriptions  and  original  figures  of  the  prin- 
cipal specimens  mentioned  or  referred  to  may  be  found  in 
the  following  writings  : — 

H.  v.  Meyer,  Reptilien  aus  dem  Lithograph.  Schiefer. 

1859.  Folio. 

v.  Quenstedt,  Pterodactylus  suevicus.     1855.     4to. 

Goldfuss,  Nova  Ada  Leopold.     XV. 

v.  Munster,  Nova  Acta  Leopold.     XV. 

A.  Wagner,  Abhandl.  Bayerischen  Akad.,  vi.,  viii. 

Cuvier,  Annales  du  Museum,  xiii.     1 809. 

„         Os semens  fos sites,  v.     1824. 
Buckland,  Geol.  Trans.,  ser.  2,  iii. 
R.  Owen,  Palccontographical  Society.     1851,    1859, 

1860,  1870,   1874. 

K.  v.  Zittel,  Palceontographica,  xxix.     1882. 

T.  C.  Winkler,  Mus.  Teyler  Archives.     1874,  1883. 

Oscar  Fraas,  Palfcontographica,  xxv.     1878. 

Anton  Fritsch,  Bohm.  Gesell.  Sitzber.     1881. 

R.  Lydekker,  Catalogue  of  Fossil  Reptilia  in  British 

Museum,  I.     1888. 

O.  C.  Marsh,  Amer.  Jour.  Science.     1882,  1884. 
S.  W.  Williston,  Kansas  University  Quarterly.     1893, 


231 


232  APPENDIX 

E.  T.  Newton,  Phil.  Trans.  Royal  Soc.     1888,  1894. 
H.  G.  Seeley,  Ornithosauria.     8vo.     1870. 

,,  Annals  and  Mag.  Natural  Hist.    1870, 

1871,  1890,  1891. 

,,  Linn.  Society.     1874,  1875. 

„  Geol.  Mag.      1881. 

Felix  Pleininger,  Palceontographica.     1894,  1901. 


INDEX 


Abdominal  ribs,  85,  154 

Accumulation  of  characters,  220 

Acetabulum,  95 

Acquired  characters,  219 

Adjacent  land,  136 

Air  cells,  10,  48 

Albatross,  23,  36,  176 

Alligator,  brain,  53  ;  pelvis,  98 

American  Greensand,  185 

—  ornithosaurs,  87,  126 

Amphibia,  4,  191 

Anabas,  17 

Anacharis,  227 

Anchisaurus,  199 

Angle  of  lower  jaw,  75 

Ankle  bones,  103,  195,  207 

Anomodonts,  192 

Ant-eater  of  Africa,  142  ;  India, 

40  ;  South  America,  40,  185 
Apteryx,  lungs.  48  ;  pelvis,  95 
Aquatic  mammals,  141 
Aramis,  scapular  arch,  113 
Archceopteryx,  58,  76,   104,   130, 

197,  211 
Aristosuchus,  129,  190,  205,  209 

Armadillo,  40,  141 

Articulation  of  the  jaw,  12,  75 

Ash  well,  177 

Atlantosaurus,  202 

Atlas  and  axis,  80,  81 

Aves,  190 

Avian  characters,  220,  222 


Backbone,  78,  84 
Banz,  148 


Barbastelle,  25 

Barrington,  177 

Barton,  177 

Bat,  38,    no,    197;   sternum   of, 

107  ;  metacarpus,  128 
Bavaria,  156,  185 
Beak,  horny,  74,  178 
Bear,  skull  of,  12  ;  femur,  IOO 
Bel  and  the  Dragon,  15 
Belodon,  202 
Bird,  80,  no,  120 

—  resemblances,  63,  65,  71,  95, 

102,    108,   113,   119,    120,  211 

Bird-reptile,  188 

Bird  wing,  128,  130 

Birds  in  flight,  22  ;  with  teeth,  76 
I   Black -headed  bunting,  47 
i   Blainville,  D.  de,  30,  193 
|   Blood,  temperature  of,  56 

Bohemia,  34 

Bonaparte,  Prince  Charles,  30 

Bones  of  birds,  variation  in,  41 

—  of  reptiles,  variation  in,  42 

—  about  the  brain,  69 

—  in  the  back,  84 
Bone  texture,  59,  209 
Bonn  Museum,  32,  85,  156 
Brain  and  breathing  organs,  55 
Brain  cavity,  in  birds  and  reptiles, 

52;  in  mammals,  221,  226;  in 
Solenhofen    pterodactyles,    54, 
Brazil,  34  [220 

Breathing  organs,  8 
Bridgewater  Treatise,  143 
British  Museum,  133,  183 
Brixton,  Isle  of  Wight,  55,  174 
Buckland,  Dean,  143,  148,  231 
Burrowing  limb,  38 

233 


234 


INDEX 


c 

Curlew,  68 

Cactus,  227 

Cuvier,  i,  27,  28,  54,  76,  77,  130, 

Calamospondylus,  203 

231 

Cambridge  Greensand,  33,  89,  176 

Cycnorhamphus,  70,  94,  171,  173, 

—  Museum,  177 

204 

Camel,  83 
Campylognathus,    68,     71,     135; 

Cycnorhamphus  Fraasii,  So,  69, 
169 

size  of,  149 

—  suevicus,  169,  170 

Canary,  47 

Cypselus,  42 

Carnivorous  dinosaurs,  129 

Carpus,  122 

D 

Caudal  fin,  91,  161 

—  vertebrae,  89,  92,  203 

Dace/o  gigantea,  63 

Ceratodus,  4,  5,  9,  17 

Darwin,  3 

Ceratosaurus,  203,  204 

Davy,  Dr.  John,  142 

Cervical  rib,  81 

Deuterosaurus,  97 

Cetacea,  40 

Dicynodon,  200 

Cetiosaurus,  198,  203 

Dicynodon  lacerticeps,  71 

Chalinolobus,  25 

Digits,  of  ostrich,   23  ;   of  ptero- 

Chalk,  pterodactyles  in,   136;  of 

dactyle,  128 

Kansas,  103,  132 

Digits    with    claws,     130;    foot 

Chameleon,  17,  51,  70;  scapula, 

bones  in,  105 

112;  sternum,  107 

Dimorphodon,    63,    64,    66,    67, 

Chameleonoidea,  191 

73>  74,  83,  90,  102,  113,  143, 

Cheek  bones,  178 

192,  194,  199,  201,  206 

Chelonia,  86,  112,  193 

Dinosauria,  6,  77,  84,  87,  95,  129, 

Chesterton,  177 

144,  198,  209 

Chlamydosaurus,  21 
Chrysochloris  capensts,  1  2  1 

Dinosaurs  from   Lias,   135,   192  ; 
from  Elgin,  201,  207;  Stuttgart, 

Classification,  192;  on  pelvis  char- 

202 ;  Trias  dinosaurs,  199,  200 

acters,  195  ;  of  dinosaurs,  198 

Diopecephalus,  168 

Clavicles,  in,  112 

Diving  birds,  23,  83,  102 

Claw,  105,  116,  183,  208 

Dolichosauria,  191 

Ccelurus,  203,  209 

Dolphin,  107 

Coldham  Common,  177 

Doratorhynchus,  173 

Collar  bone,  III 

Dorygnathus,  74,  148 

Collini,  27 

Dragons,  3,  15,  17 

Comparison  with  dinosaurs,  198  ; 

Drumstick  bone,  103,  195 

of  pelvis,   204,   206  ;  of  skulls, 

Duck,  22,  83 

192,  199,  201 

Cope,  Professor,  31,  34 

E 

Coracoid,  109,  112,  113 

Cordylomorpha,  191 

Echidna,  75,  76,  95,  100 

Cormorant,  70,  174!  sternum,  108 

Edentata,  185 

Corpora  quadrigemina,  221 
Crisp,  Dr.,  on  pneumatic  skeleton, 

Edentulous  beak,  153 
Eichstadt,  32 

47 

Elephant,  head  of,  46 

Crocodile,     characters    of,     217  ; 

Enumeration  of  characters,   223, 

heart,  56  ;  lung,  9  ;   shoulder- 

225 

girdle,  in  ;  skull,  46;  vertebrae, 
79 

Ephesus,  winged  figure,  16 
Epiphysis  to  first  phalange,  123 

Crocodilia,  190                                      Exoccetus,  18 

INDEX 


235 


Extinctions,  129 

Eye  hole,  144  ;  sclerotic  bones  in, 
65 


Farren,  William,  34 

Femur,  100 

Fibula,  102,  183,  206 

Fifth  outer  digit,  132 ;  in  foot,  145 

Figure  from  temple  at  Ephesus,  16 

First  phalange,  151 

Fish-eating  crocodile,  137 

Flight,  organs  of,  17  ;  in  bats,  25 

Flying  limb,  38 

Flying  fishes,  18,  57  ;  foxes,  26  ; 

frogs,  19,   197;  gecko,  21,  24; 

lizards,   20 ;   reptiles,    37,    46 ; 

squirrel,  24 

Foot,  104;  digits  in,  105,  146 
Fore  leg,  102,  206 
—  limb,  38,  107,  116,  120 
Four  claws,  147 
Fox,  Rev.  W.,  55,  174 
Fraas,  Professor  Oscar,  172,  231 
Frigate  bird,  vertebra  of,  86,  174 
Frog,  lungs  of,  8 
Furculum,  114 


Gaudry,  Professor  A.,  31 

Gavial,  136 

Gecko,  21,  23 

Genera,  comparison  of,  192 

Geological  distribution,  186 

Gills,  4 

Giraffe,  38,  39 

Glossy  starling,  47 

Golden  eagle,  120 

—  mole,  121 

Goldfuss,  30,  231 

Granchester,  177 

Great  ant-eater,  40,  185 

Guillemot,  102 

Gull,  22 

H 

Haarlem,  Teyler  Museum  at,  32 
Habits,  probable,  134,  176,  198 
Hairless  skins,  141 
Hand  in  mammals,  38 


Harston,  177 
Haslingfield,  177 
Hastings,  174 

Hatteria  lung,  9,  27  ;  brain,  53  ; 
skull,    70,    77 ;    ribs,    86 ;    a 
reptile  type,   13 
Head,  characters  of,  76 
Heidelberg  Museum,  32,  54,  159 
Herpetomorpha,  191 
Heron,  65,  174 
Hesperornis,  76 
Hind  foot,  104,  135 
—  limb,  93,  99,  I59i  2o6 
Hip-girdle  in  whale  tribe,  39,  159 
Homceosauria,  191 
Horningsea,  177 

Horse,  metacarpus  of,  127;  verte- 
brae of,  79 

Humerus,  46,  117,  217 

Huxley,  Professor,  31,  89,  154, 
188 

Hyo-manibular  arch,  13 

Hypothesis  of  descent,  226 

Hyrax,  101 

I 

Ichthyornis,  76 

Ichthyosaurus,  6,  191 

Iguanodon,  209 ;  pelvis,  206 

Ilium,  93,  95,  96,  98,  204 

Instep,  105,  207 

Inherited  characters,  217 

Interclavicle,  in 

Ischium,  93,  96,  203,  204 

Isle  of  Wight,  174 

J 

Jaw,  in  birds,  12 ;  in  fishes,  13  ; 
in  mammals,  12;  in  reptiles, 
13  ;  in  pterodactyles,  63  ;  sus- 
pension of,  II,  74>  76 

—  lower,  75 


Kansas,  Chalk  of,  72,  103,  115 

University  Museum  of,  181 
Kelheim,  32 
Keuper,  33 
Kimeridge  Clay,  132 
Kingfisher,  63 
Kiwi,  23 


236 


INDEX 


Labyrinthodontia,  191 
Lachrymal  bones,  67 
Laramie  rocks,  34 
Largest  ornithosaur,  133 
Lateral  vacuities  in  skull,  147 
Lawrence  in  Kansas,  181 
Lengths  of  bones,  146 
Lepidosiren,  17 
Lias,  33 

Lithographic  Slate,  35,  156 
Lizards,  20,  21,  27,  123 
Llama,  neck  of,  79i  83 
Loach,  swim  bladder  of,  52 
Lower  jaw,  12,  74,  76,  149 
Lumbar  vertebrae,  89 
Lungs,   47 ;    in  apteryx,   48 ;    in 

chameleon,  51  ;  in  ostrich,  49  ; 

in  reptiles,  8,  9,  51 
Lydekker,  R.,  160,  169,  231 
Lyme  Regis,  33 

M 

Macrocercus,  palate  of,  71 

Malar  bone,  67 

Mallard,  22 

Mammal,  8,  12,  24,  79,  53,  95 

Mammalia,  38,  141 

Mammalian  characters,  12,  220 

Mammoth,  141 

Manis,  40,  57,  142 

Manubrium  of  sternum,  108,  109, 

183 

Marrow  bones  in  a  bird,  134 
Marsh,  Professor  O.  C.,  31,  72, 

90,    115,    121,    131,    140,    160, 

165,  180,  181,  210,  231 
Marsupial,  70,  94,  99 
Megalosaurus,  129,  198 
Merganser,  108 
Merry-thought,  114 
Metacarpus,   116,  124,   126,   128, 

130 

Metatarsal  bones,  104,  207,  208 
Meyer,  Hermann  von,  31,  45,  46, 

85,    105,    108,    121,    160,    192, 

231 

Moa  of  New  Zealand,  35 
Mole,     humerus,     38 ;     sternum, 

107 


I   Monotremes,   70,    94,    in,    121, 

185,  218 
Mososaurus,  77 
Movement  of  the  leg,  101 
Mugger,  137 

Munich  Museum,  32,  159 
Munster,  von,  231 
Muschelkalk,  184 
Museum,     32,     156,    231,     159; 

Natural  History,    133,  231 
Myrmecophaga,  185 

N 

Names  of  genera,  183 

Natural  History  Museum,  38,  231 

Neck,  79;  in  Dimorphodon,  145; 

in  Giraffe,  39 ;   in  Llama,  79  ; 

in  Pterodactyles,  80;  in  Whales, 

39 
Newton,  E.  T.,  55,  70,  158,  160, 

201,  232 
New  Zealand  Bat,  25 

Hatteria,  68 

Niobrara  rock,  183 

Nostril,    bones    round    the,    62 ; 

small,    147 
Notarium,  87,  115 
Nothosauria,  192 
Nusplingen,  32 
Nyctodactylus,  115,  180 


Obliteration  of  characters,  216 

Opercular  bones,  13 

Ophidia,  52,  191 

Optic  lobes,  53,  221 

Organs  of  flight,  17 

Ornithischia,  190,  198 

Ornithocephalus,  166 

Ornithocheirus,  atlas  and  axis,  81  ; 
brain,  55,  69;  carpus,  124; 
cervical  vertebra,  83,  179;  claw 
phalange,  129  ;  coracoid,  109  ; 
femur,  100 ;  pelvis,  98 ;  pubic 
bones,  194 ;  sternum,  109 ; 
shoulder-girdle,  115;  remains, 
176;  teeth,  74,  76;  absence  of 
teeth,  138 

Ornithocluims  machterot  hynchus, 
139;  microdon,  139 


INDEX 


237 


Ornithocheiroidea,  193 

Ornithodesmus,  neck  bones,  173, 
175;  coracoid,  109,  116;  dorsal 
vertebrae,  86 ;  remains  of  O. 
latidens,  173;  O.  sagittirostris, 

175 

Ornithomorpha,  189 
Ornithorhynchus,  40,  53,  95,  117 
Ornithosauria,  30,  31,  50,  52,  58, 

72,  89,  95,   104,  108,  125,  132, 

133,  143,  187,  190,  192,  216 
Ornithostoma,   66,  69,  72,    180 ; 

lower  jaw,  75,  76  ;  pelvis,  98  ; 

sternum,   no;  phalange,  122; 

size,  133  ;  skull,  181,  182 
Ornithosuchus,  201 
Orycteropus,  96 
Ossa  innoininala,  93 
Ossified  ligaments,  150 
Ostrich,  23,  45,  49,  113,  129 
Owen,  Sir  R.,  31,  36,  46,  48,  no, 

117,  143,  172,  176,  180,  231 
Owl,  46,  53 
Oxford  Clay,  33,  156 
—  University  Museum,  154 
Ox,  vertebra  of,  79  ;  metacarpus, 

127 


Palate,  bones  of,  71 

Pangolin,  142 

Pappenheim,  32 

Parallel  groups,  215 

Parrot,  71 

Patagial  membranes,  227 

Pelican,  174 

Pelvis,  88,  94-98,  15 r,  195,  202, 

204,  206 

Penguin,  41,  42,  104,  176 
Periophthalmus,  17 
Peterborough,   bones  from,    113, 

156 
Phalanges,  129,  132;  wing  finger, 

Phillips,  Professor  John,  155 
Pigeon,  119 
Platydactylus,  21 
Platypus,  214 

Plesiosaurus,  6,  73,  75,  93,  189 
Pleinyiger,  149,  232 
Pneumatic  foramina,  45,  83,  88, 
132,  209 


Pond,  Mr.,  34 

Porcupine,  40 

Porpoise,  38,  73,  141,  200 

Premaxillary  bones,  77,  200,  205 

Prepubic  bones,  94,  96-98,  194, 
204,  205 

Protorosauria,  192 

Ptenodracon  brevirostris,  64,  99, 
167,  169,  192 

Pteroclactyle  aspects,  35 ;  avian 
characters,  222;  beak,  200; 
brain,  53;  coracoid,  113  ;  dis- 
covery, 27,  33  ;  foot,  104  ;  fore 
limb,  117;  history  in  Germany, 
31.  148  ;  hand,  130  ;  hind  limb, 
100;  long  tails,  156;  palate, 
.71;  sacrum,  89 ;  short  tails, 
165  ;  size,  35,  133  ;  sacrum,  89  ; 
skull,  192;  teeth,  73;  vertebra?, 
80 

Pterodactyles  from  Kansas  Chalk, 
177,  181 

—  from  Lias  Clay,  135,  147,  152 

—  from  Neocomian  Sand,  176 

—  from  Oxford  Clay,  155 

—  from  Purbeck  beds,  1 73 

—  from  Solenhofen  Slate,  156, 158 

—  from  Stonesfield  Slate,  153,  158 
Pterodactylia,  30,  165,  193,  199 
Pterodactylus  antiquus,  1 67  ;  bre- 

virostris,  99,  167,  169  ;  crassi- 
rostris,  156  ;  dnbius,  87,  96,  97, 
2OT,;e/egans,  169;  Fraasii,  169; 
grandipelvis ,  87,  90 ;  grandis, 
102,  167,  169  ;  Kochi,  12,  61, 
87,  90,  168,  169 ;  longirosiris, 
28,  90,  96,  101,  103,  105,  167, 
169  ;  micronyx,  105,  169  ; 
rhamphastinus ,  183  ;  scolopa- 
ciceps,  105,  1 66;  sfectabilis,  83; 
snevicus,  169 

Pterodermata,  194,  199 

Pteroid  bone  of  first  digit,  121 

Pteromys,  24 

Pterosauria,  187,  193 

Pterygoid  bones,  72,  147 

Pythonomorpha,  191 


Quadrate  bone,  12,  68,  77 
Quenstedt,  231 


238 


INDEX 


Rabbit,  227 

Radius,  119,  120 

Redshanks,  22 

Relation  between  head  and  tail, 

'57,  193 

Reptile,  6,  79,  80 
Resin,  136 
Restorations — 

Campylognathus,  palate  of,  71 

Dimorphodon,  143,  147,  164 

Ornithocheirus,  164 

Ornithostoma,  164,  183 

Ptenodracon,  167 

Pterodactylus,  29,  30 

Rhamphocephalus,  164 

Rhamphorhynchus,  161,  164 

Scaphognathus,  163 
Rhacophorus,  19 
RhKtic  beds,  184 
Rhamphocephalus,  113,  136,  153 
Rhamphorhynchus,  118, 192;  foot, 

104;  hind  limb,  99;  pelvis,  95; 

sacrum,   88 ;    skull,    54,   63-^6, 

69;    sternum,    108 ;    tail,    91; 

teeth,  73;  tibia  and  fibula,  103; 

web-footed,  105 
Rhamphorhynchus      citrtimanus, 

163 ;       hirundinaceus,       163  ; 

iongimanus,     164 ;    phyllurus, 

91,    165 

Rhinoceros,  40,  141 
Rhopoladon,  97 
Rhynchocephala,  192 
Roc,  36 
Rochester,  136 
Running  limb,  38 
Ryle,  Bishop,  17 


Sacrum,  87,  88 
St.  George,  15 
St.  Ives,  156 
Sarcorhamphus,  102 
Saurians,  27 

Saurischia,  190,  195,  198,  199 
Sauromorpha,  191,  192 
Sauropsida,  188 
Sauropterygia,  192 
Scaphognathus,  64,  85,   140,  152, 
192,  212 


Scaphognathus  crassirostris,  73-5, 

83 

Scapular  arch,  III,  113 
Scelidosaurus,  135 
Sclerotic  circle,  65 
Seals,  41 

Sedgwick,  Professor  Adam,  v,  46 
Shillington,  77 
Shoebill,  67 
Shoe-shaped  prepubic  bones,  204, 

205 
Short-tailed    pterodactyles,     165, 

193 
Shoulder  -  girdle,    107,   in,    114, 

i IS..  '83 

Siberia,  141 

Simultaneous  origin  of  characters, 

214,  224 

Skin  covering,  40,  41,  58,  139.  140 
Skulls,  68 
Sloth,  112 
Snipe,  47,  68 
Solenhofen  Slate,  28,  32,  88,  153, 

"56 

Sommernng,  29 
South  African  reptiles,  1 88,  208, 

216 

Spotted  fly-catcher,  47 
Squamosal  bone,  12,  13 
Sternal  ribs,  1 10 
Sternum,  107,  158 
Stonesfield  Slate,  33,  88,  153 
Structures  common  to  reptiles,  224 
Stuttgart  Museum,  32,  172,  203 
Swanage,  172 
Swan,  neck  of,  80,  113 
Swift,  50 

Swimming  limb,  38 
Synotus,  25 
Syrinx,  48 


Tail,  description  of,  90 ;  in  Cre- 
taceous Pterodactyles,  193 

—  long,  156;  short,  166 ;  in 
Dimorphodon,  145 ;  in  Orni- 
thocheirus, 179 

Tanystrophceus,  long  vertebrae  in, 
79 

Tarsal  bones,  102,  207 

Tarso-metatarsus.  128 


INDEX 


239 


Teeth,  73,  137,  138  ;  in  porpoise, 

Variation  of  bones  in  vertebrae,  225 

40 

Vertebrae,  caudal,  89,  92,  203 

Temperature  of  blood,  56 

—  cervical,  173,  179,  203 

Temporal  arches,  68 

—  dorsal,  86 

—  bone,  12 

Vertebral  articulation,  82,  224 

—  fossa,  67 

—  column,  78 

Teredo,  137 

Vulture,    neck   vertebrae   of,   80  ; 

Texas  fossils,  216 

tibia  and  fibula  of,  IO2 

Thecospondylus,  209 

Vomer,  147 

Theriodont  pelvis,  97 

Vomerine  bones,  72 

—  reptiles,  75  ;  of  Russia,  96,  97  ; 

of  South  Africa,  96,  117 

W 

Theropsida,  188 
Thigh  bone,  100,  206,  211 
Three  claws,  146,  197 
Tibia,   102,   195  ;  in  Iguanodon, 

Wagler,  29 
Wagner,  Andreas,  30,  148,  231 
Walker,].  F.,  54 
Wealden  beds,   Pterodactyles  in, 

207 
Toothless  mammals,  40 
—  pterodactyles,   138,   181  ;  beak 

55,  84  ;  bones  in,  135,  136,  173 
Weight  of  Pterodactyle,  106 
Whinchat,  47 

of  pterodactyles,  150 
Transition  from  reptiles  to  birds, 

Whitby,  33,  135 
Williston,   Professor  W.   S.,    75, 

211 

82,  92,  98,  105,  no 

Tree  frogs,  21 

Willow-wren,  47 

Trias  dinosaurs,  199 
Triceratops,  pelvis  of,  204 
Trout,  139  ;  of  New  Zealand,  228 

Wing  finger,  116,  130,  133,  151 
178,  197 
—  membrane,  32,   121,  140,  and 

Tuatera,  13 
Tiibingen  Museum,  32 
Tundras,  141 
Tunny,  57 

frontispiece 
—  metacarpal,   123  ;    in    Dimor- 
phodon,  151  ;  in  Ornithostoma, 
184  •  in  bats    1^1 

Turtles,  neck  bones,  79 

Wings  of  Dragons,  16 
Winkler,  T.  €.,231 

U 

Woodwardian  Museum,  34 

Ulna,  description  of,  119 
Uncinate  process  of  ribs,  85 
Unlimited  time,  228 

Wood-wren,  47 
Wrist  bones,  122 
Wiirtemberg,  33 

Upper  arm  bone,  117 
—  Greensand,  remains  in,  136 

Y 

—  Lias  of  Whitby,  147 

Yale  College  Museum,  32 

—  Oolites,  185,  195 

York  Museum,  34,  176 

V 

Z 

Variation  of  bones  in  mammals,  38 

Zittel,  Karl  von,  31,  157,  165,  231 

—  in  Pterodactyles,  229 

Zygomatic  arch,  67 

PRINTED   BY 

WILLIAM    BRKNDON    AND    SON 
PLYMOUTH 


borrowed 


OCT1719» 

.EC'D  C.L  OCT  0  7  '< 


Phys.Sci. 

QE862       Seeley,  Harry  G. 


Dragons  of  the  air,  an 
account  of  extinct  flyin 
reptiles. 


' FACIUIY 


Physical  Sciences  Library 

University  of  California 

Riverside 


